Standing all day on a hill (pilots call us 'hill monkeys') and waiting for a low flying aircraft to come by is perhaps not everyone's choice for a day out. For me it is both relaxing and at times exhilarating during the few seconds it takes for an aircraft, travelling at seven miles a minute (420 knots or 778 km/h), to pass. It's the anticipation of an aircraft appearing at any moment and the desire for stunning image, that keeps you going.

Low level photography is hit and miss, it requires a great deal of perseverance and patience. Some days you may get a dozen or more fly-by's, other days you could get nothing at all. Trying to second guess where the day's low level flying operations will be is extremely difficult, luck plays a major part in getting some good low flying action.

"One of the 100 best images published in Aircraft Illustrated"

Aircraft (Illustrated) Magazine in September 2009 produced volume 1 of the glossy 'Collector's Edition - 100 Best Pictures'
Introduction by Allan Burney, Editor; 'Welcome to 100 of the world's greatest aviation images, a celebration of the skill and artistry of today's digital aircraft photographer. Over the last 30 years it has been my privilege to work with the best aviation photographers in the world and to view and edit their work into the pages of Aircraft Illustrated which continues the tradition of bringing you the very best in aviation photography'.

Right: My image of a 12(B) Squadron Tornado GR.4 flying at low level through Wales in October 2008, was selected as one of the 100 best images to be published in 'Aircraft Illustrated' in the last five years. Of the images chosen this was the only one taken from a hill side of an aircraft at low level.

Where to go on the day
Numerous valleys in Wales, the Lake District and Scotland are used for low flying and are suitable for low level photography. Where I go is dependent on the weather and the line the aircraft tend to fly a particular location. Light and the angle the aircraft presents to the camera, go together to make the image.
To get the best results you need to get above the action and as close as possible. Tight valleys, or choke points, with steep sides are essential, if you are to get shots from above or the side with the ground in the background, thus emphasising low level flying action. Positioning yourself on long straight valleys will produce aircraft side-on shots, the inside of a bend will produce top shots and the outside of a turn will produce bottom shots.

Above left: This 208(R) Squadron Hawk was captured in the early morning light (09:10) in April 2007 it stands out nicely against the misty background. DSLR x1.6 sensor + Canon EF 300mm f2.8L f.7.1 1/500 at ISO 200.

Above right: This image from August 2004 of Harrier GR.7 (ZG857) from the former Fast Jet & Weapons OEU was the first in a sequence and has been cropped quite a bit. The angle of the aircraft is very attractive and the gentle light from behind enhances the aircraft's contours. This image was selected for the RAF Calendar. 
 

How high you climb affects the angles the aircraft presents to the camera, the position of the sun is another major influence on where to go. With bright sun behind you a crisp bright image is guaranteed. As the sun moves across the sky during the day, then swapping valley sides can be worth while. Shooting toward the sun naturally produces silhouettes and flare with a corresponding loss of detail, which is usually undesirable. The time of the year and the line of the sun should also be taken into account. During the winter months when the sun is lower, shadows can move up the valley sides during the afternoon.
On overcast days the reasons for avoiding south facing hillsides are negated. Defused light reduces the depth of shadows and highlights so that shooting into the sun is easier, particularly as you tend to shoot down to the aircraft flying below you. The final decision on which hill to climb is sometimes made on arrival, when local conditions can be properly assessed. With all these variables there is plenty of scope for good and not so good decisions to be made, which is half the challenge.

Above left: In north to south running valleys it is not always possible or desirable to swap sides at mid-day. Shooting into the sun for part of the day is the consequence in sticking to one side of the valley. This F-15E Strike Eagle was taken mid-morning in October 2008. Reducing exposure by up to one f-stop to avoid blown out highlights is essential if detail is not to be lost from the aircraft's upper surfaces. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/640 at f.5 with -2/3 exposure compensation and ISO 200.

Above right: Jaguar T.4 of 6 Squadron just before their disbandment in May 2007. The weather was overcast and so I was able to capture this shot from a south facing hill in Wales during the mid-afternoon. The damp weather has caused attractive vortices to be formed from the wing tips. DSLR x1.6 sensor + Canon EF 300mm f2.8 L f.4 1/640 ISO 200.
 

When to go and weather to avoid
There appears to be very little pattern to the daily movements. Fridays can be slow in the afternoons, but not always. Expect to see low flying anytime between 09:00 and 17:00, however there are always exceptions, the F-15E Strike Eagle (left) was shot at 18:15 on a September evening in 2009, when the sun was very slow making it almost impossible for the pilot to fly at low level towards the setting sun.

I pick my days to go to the hills carefully, looking for good weather before I make the decision go. With a limited amount of time available in the year, I try to ensure I get a dry and bright day, for a good set of images. As the weather is often unpredictable I have been caught out with poor weather on numerous occasions. Standing on a bleak hill in the rain or in low cloud is not much fun. Cold weather is never a problem if you wear the right clothing.

Low cloud is a big hazard to pilots flying at low level. If they can't see a hole in the cloud to descend through to low level, they may request radar assistance in certain areas in the UK Low Fly System (UKLFS), otherwise intended low level sorties are aborted. In Wales an instructor from RAF Valley will fly the 'Weather Hawk' before students take to the air. These experienced pilots will fly through all the main valleys to make sure that there is no lingering low cloud, before declaring them clear and safe for the students. The 'Weather Hawk' will normally fly between 08:00 and 09:00, depending on the time of the year.

Right: The cloud descended to cover the hilltops but not too low to prevent this Hawk from RAF Valley from flying its low level sortie.

Strong winds have an adverse affect on low level photography, photographers should always take wind speeds into account. Cross-winds over 25 kts could be enough to cancel planned sorties. Mission planners are very safety conscious and to take into account the risks to a pilot having to eject. Strong winds will effect the sea state, if the waves are too high then it could be impossible to pluck an ejected pilot from the sea. Strong winds also make it hazardous to eject over land, as they can blow a pilot into a mountainside. Pilots often can't get actual surface wind speeds, but will use 2,000 foot wind speed forecasts and set a limit for low level flying at winds of 50 kts or more. The aircraft's Inertial Navigation System (INS) using motion sensors computes the amount of drift and therefore the wind speed during flight. Turbulence is another issue affecting safety for flying at low level. A 50 kt wind in a valley will generate turbulence that could take the aircraft over its G limit, especially if carrying a bomb load. In reality low level photographer will often find it too difficult to handle telephoto lenses in winds well below those that pilots are unable to fly.

Apache AH.1 (ZJ190) of Army Air Corps 662 Squadron, 3 Regiment in June 2006  
Reducing the camera's shutter speed for propellers and rotors is used to increase blur and show movement, 
but this increases the risk of a soft or blurred image. DSLR x1.6 sensor + Canon EF 300mm f2.8L f.11 1/125.

The best shots from the best spots:
Most of the images in this report were taken in the hills of Wales (LFA 7) and in Cumbria (LFA 17).
 

Photogenic angles are what I constantly look for, with the right combination of the location, weather and time of day it will produce the best images.

Left to right: MC-130H Combat Talon II (87-0024) of 7th SOS, 352 SOG using callsign 'Talon 71' in May 2011. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/320 at f.7.1 with -1 exposure compensation and ISO 100.
Tornado GR.4A (ZA402) is used as a systems test aircraft operated by BAE Systems out of Warton and seen in September 2006.
Tornado GR.4 (ZA473/-) of 12(B) Squadron in October 2008. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/640 at f.6.3 with -2/3 exposure compensation and ISO 200.
F-15E Strike Eagle (91-0304 'LN') callsign 'Dirty 51' of 492FS, 48FW it was first of a pair making their passes at 18:14 in September 2009, this aircraft was later to crash in Libya on March 22, 2011 during operation Odyssey Dawn to secure a no fly zone, both crew ejected safely. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 at f.4.5 with -2/3 exposure compensation and ISO 200.  

Left to right: Tornado F.3 (ZE734 'JU') in 111 Squadron special colours in July 2009. 
Typhoon F.2 (ZJ914 'DE') of 11(F) Squadron using callsign 'Typhoon 27' in May 2008. DSLR x1.6 sensor + Canon EF 300mm f2.8L and x1.4 extender at 1/800 f.9 ISO 200 with -2/3 exposure compensation.
F-15E Strike Eagle (96-0205 'LN') of the 492FS, 48FW based at RAF Lakenheath in early morning in October 2008.
Harrier GR.9A (ZD433 '45A') of 1(F) Squadron with an impressive array of mission markings from its deployment to Afghanistan in November 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 f.7.1 ISO 200 with -1 exposure compensation.

Left to right: Tornado GR.4 (ZA452 '021') of 31 Squadron with 67 degree swept wings and after-burners in June 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 f.8 ISO 200 with -1.1/3 stop exposure compensation. 
US Special Forces MC-130H Combat Talon II (88-0195) in August 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/250 f.5 ISO 100 with -2/3 stop exposure compensation.
A-10A Thunderbolt II (82-0650 'SP') of 81st FS, 52nd FW deployed to RAF Lakenheath in July 2007, while the runway at their home base of Spangdahlem in Germany was being resurfaced.
Tornado GR.4 (ZA404 '013') in 14 Squadron colours and using callsign 'Valkyrie 2' in March 2011. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 f.9 ISO 200 with -1 stop exposure compensation.

Left to right: First of a pair of Typhoon FGR.4's (ZJ918 'QO-L') callsign 'Rampage' of 3(F) Squadron in Wales in October 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 f.3.5 ISO 200 with -2/3 stop exposure compensation.
Red Arrow Hawk T.1A (XX253) callsign 'Red 11' on its way from RIAT at Fairford to RAF Valley before continuing on to its home base at RAF Scampton in July 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 at f.5 with -2/3 exposure compensation and ISO 200.
Hawk T.1W (XX178) of 19(R) Squadron fitted with CBLS (Carrier, Bomb, Light, Store) pods under each wing. The CBLS are sometimes fitted for training sorties to show the student the differences of the handling and higher fuel consumption with stores fitted. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/640 f.2.8 ISO 200 with -2/3 stop exposure compensation.
Hawk T.1 (XX244) in 208(R) Squadron colours in March 2011. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 f.10 ISO 200 with -1 stop exposure compensation.

Top shots of aircraft with the opposing hillside in the background are perhaps the most exciting of all low level images they demonstrate low flying perfectly. In low humidity vortices from the wing's upper surfaces and a blurred background further emphasise action.

RAF Lakenheath based F-15E Strike Eagle it was first of a pair in June 2005

Left to right: BAE Systems Hawk 100 demonstrator (ZJ951) in its new paint scheme applied specially for the SBAC show at Farnborough to which it was flying in July 2006.
Hawk T.2 (ZK025) with 19(R) Squadron in August 2011. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 at f.5 with -1 exposure compensation and ISO 200.
Alpha Jet (ZJ645 '45') in a new black and white QinetiQ scheme in June 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L plus x1.4 extender at 1/640 at f.4.5 with -2/3 exposure compensation and ISO 200.
Alpha Jet (ZJ646) with DPA/AFD/QinetiQ at Boscombe Down in July 2007.

Left to right: Tornado F.3 of 111 Squadron (ZE158 'HG') from RAF Leuchars in August 2005.
Tornado GR.4 (ZG775 '134') in 12(B) Squadron colours but using callsign 'Marham 31' when on a low level sortie through Wales in November 2007. Remarkably if you look very closely the third panel from front on right is lifting during the high-G turn. RAF Marham phoned back following my warning call and inspection to say they were "extremely grateful" for alerting them of the potentially serious problem.
Typhoon T.1 (ZJ814 'QO-Z') of 3(F) Squadron in May 2008.
Hawk T.1 (XX234) of 208(R) Squadron in March 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/640 at f.7.1 with -1 stop exposure compensation and ISO 200.

Left to right: F-15E Strike Eagle (91-0324 'LN') of the 494 FS, 48 FW in October 2008. DSLR x1.6 sensor + Canon EF 300mm f2.8L plus an x1.4 extender at 1/640 at f.8 with -2/3 exposure compensation and ISO 200.
Harrier GR.9 (ZD406 '35') in joint 800/801 Naval Air Squadron markings just before sunset at the end of November 2007. In March 2007 the Naval Strike Wing (NSW) was formed comprising elements of 800 and 801 Squadrons. 
Tornado GR.4 (ZD810 '102') it has 'Spirit of Speyside' nose art and was in XV Squadron markings in October 2008. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/640 at f.7.1 with -2/3 exposure compensation and ISO 200.
French Air Force Alpha Jet E (E104 '705-TG') in June 2010.  

Left to right: Unmarked Harrier GR.9 (ZD375 '23') in June 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 at f.5.6 with -2/3 exposure compensation and ISO 200.
Harrier GR.9A (ZD349 '15') with the Naval Strike Wing in July 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/640 at f.3.2 with -2/3 exposure compensation and ISO 200.
F-15E Strike Eagle (98-0133 'LN') callsign 'Dirty 52' of 492 FS, 48 FW in September 2009 at 18:17. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 at f.3.5 with -2/3 exposure compensation and ISO 200.
Harrier GR.9 (ZD438 '50') still in its old 4(AC) Squadron markings in May 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/1000 at f.9 with -1 stop exposure compensation and ISO 200.

Going knife edge

Left to right: Two-seat Jaguar T.4 (XX841) when operating with QinetiQ at Boscombe Down.
Hawk T.1 of 4 FTS from RAF Valley.
Harrier GR.9 (ZG859 '91') in 1(F) Squadron markings, at 17:20 in May 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/1000 at f.9 with -1 stop exposure compensation and ISO 200.
Tornado GR.4A (ZA401 '012') with 2 Squadron and fitted with a (AN/AAQ-28) Litening targeting pod in March 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L and x1.4 extender at 1/800 at f8 with -1 stop exposure compensation and ISO 200.

Left to right: Tornado GR.4 (ZA370 '004') in June 2009.
Harrier GR.9 (ZD468 '58') in June 2009.
Typhoon T.1 (ZJ814 'QO-Z') of 3(F) Squadron in May 2008.

Bottom shots from the outside of a turn, showing weapons in the case of frontline fighters are well worth going for.

Tornado GR.4A (ZG705 'J') of 13 Squadron RAF Marham, carrying inert practice bomblets in two CBLS (Carrier, Bomb, Light Stores) pods.
DSLR x1.6 sensor + Canon EF 100-400mm L IS (at 400mm) f.5.6 -1/2 exposure compensation 1/350 ISO 200.

Left to right: Harrier GR.7 (ZD379 '27') then of 3(F) Squadron taken in September 2005. The Harrier is fitted with two dummy 25mm cannon pods, as a useable cannon had yet to be delivered by Royal Ordnance. The dummy weaponry is carried to produce a 'ground cushion effect' required for Short Take-Off and Vertical Landing (STOVL). Life Improvement Devices (LID's) with or without a TIALD thermal imaging laser pods are also be carried for the same reason. Low Flying late in the afternoon, the sun having just caught the Harrier for this single frame.
Tornado F.3 (ZE254 'UD') of 25(F) Squadron from RAF Leeming in June 2005.
F-15E Strike Eagle (00-3002 'LN') of the 494^th Fighter Squadron, 48^th Fighter Wing in February 2008.
Tornado GR.4 (ZD792 '100') of 13 Squadron with a Thermal Imaging Airborne Laser Designator (TIALD) pod fitted under the fuselage, in August 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/640 at f.4 ISO 200 with -1/3 exposure compensation. 

Left to right: Hawk T.1 of the Royal Navy based at RNAS Culdrose in September 2003. DSLR x1.6 sensor + Canon EF 300mm f2.8L with x1.4 extender 1/1000 at f.7.1 ISO 200.
Hawk T.1A of 19(R) Squadron fitted with and carrying a 30mm Aden Mk.4 Cannon pack and two CBLS (Carrier, Bomb, Light Stores) pods on the wing pylons in November 2008.
Hawk T.1 (XX244) of 208(R) Squadron in May 2010.

Left to right: Tornado GR.4 (ZA562 '051') devoid of squadron markings in May 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L with x1.4 extender 1/1000 at f8 ISO 200 -1 stop exposure compensation.
Typhoon FGR.4 (ZJ942 'DH') in July 2011. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/1000 at f7.1 ISO 200 -1 stop exposure compensation.
Tornado GR.4A (ZA404 '013') of 2 Squadron in January 2012. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/640 at f5 ISO 200 -1 stop exposure compensation.

Side on shots showing squadron markings for use as an historical record.

Jaguar GR.3 (XZ394 'FG') with 41 Squadron when based at RAF Coltishall in June 2005.

Left to right: One of two Hawk T.1's (XX219) specially painted for the 2004 display season, it was inscribed '1974-2004 30 years'. As there is an increased risk of a bird strike when flying at low level, it was been decided not to fly specially painted Hawks at low level until the display season have finished. It was photographed flying low through the Lake District in December 2004.
Hawk T.1 (XX307) in the new paint scheme for the 2007 display season. August 2007.
Alpha Jet E (E104 '705-TG') from the French Air Force's (Armée de l'Air) Ecole de L' Aviation de Chasse 00.314 based at Tours during an exchange with 208(R) Squadron in June 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/800 at f.5 ISO 160 with -1 stop exposure compensation.
Hawk 132 (ZK121) is with BAE Systems at Warton being tested prior to delivery to the Indian Air Force in May 2008. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/800 at f.9 ISO 200 with -2/3 exposure compensation and x1.4 extender.

Left to right: Tornado GR.4 (ZA551 'AX') in full 9 Squadron markings before Tornado fleet numbering had taken hold in June 2006.
Typhoon FGR.4 (ZJ919 'DC') of 11(F) Squadron in September 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/640 at f.5 ISO 200 with -2/3 exposure compensation. 
Dominie T.1 (XS737 'K') of 55(R) Squadron which is part of 3 FTS based at Cranwell which approached quite high, as Dominie's operate lower speeds (210 knots or two miles a minute), I was able to scramble up the hill a little and was able to catch it as it passed in front of the high peak in front, December 2005. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/500 at f.5.6 ISO 200 with -2/3 exposure compensation.
Tucano T.1 (ZF319) in stunning 2009 display 'shark' markings in August 2009 through the Lake District. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/320 at f.7.1 ISO 200 with -2/3 exposure compensation.  

Left to right: Tucano T.1 (ZF142) using callsign 'Linton 17' at low level in Wales before going on to RAF Shawbury in March 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/320 at f.5 ISO 100 with -2/3 exposure compensation.
Hawks T.1 (XX156) of 208(R) Squadron in October 2008. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/640 at f.5 ISO 200 with -2/3 exposure compensation.
Unmarked Harrier GR.9 (ZD463 '53') in June 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/800 at f.7.1 ISO 200 with -1 stop exposure compensation.
C-130J Hercules C.5 (ZH884) of 30 Squadron in March 2010. DSLR x1.6 sensor + Canon EF 70mm-200mm (140mm) f2.8L at 1/160 at f.11 with -1 stop exposure compensation and ISO 100.

Left to right: The seldom seen MC-130H Combat Talon II (88-0191 callsign 'Talon 71') of 7 SOS, 352 SOG based at Mildenhall in August 2009. DSLR x1.6 sensor + Canon EF 70-200mm (200mm) f2.8L 1/320 at f.8 ISO 160 with -2/3 exposure compensation.
Tornado GR.4A (ZA369 '003') first of a pair from of 13 Squadron in August 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/640 at f.4.5 ISO 200 with -1/3 exposure compensation.
Hawk T.1W (XX283) of 19(R) Squadron in December 2009. It is fitted with a 30mm Aden Mk4 Cannon pack. The gun can carry 120 rounds of ammunition and has a rate of fire of 1200 rounds per minute. It is used by 19(R) Squadron for strafing practice on the range at RAF Pembrey Sands on the South Wales coast or for Air to Air firing at a banner towed by another Hawk. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/640 at f.5 ISO 200 with -2/3 exposure compensation.
Super King Air B200 (G-RAFP) of 45(R) Squadron in June 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/250 at f.10 ISO 200 with -1.1/3 exposure compensation ISO 100.

Get in close for cockpit shots. If you choose your position well with a long lens you will almost see the pilot eye to eye. From above you may be able to see the pilot with his low level flying map on his lap!

Harrier GR.7A of 800 NAS from RAF Cottesmore it was just back from Afghanistan and captured in Wales in April 2006.
One of a sequence of frames which made four different magazines (five in total), a book and a MOD publication!
DSLR x1.6 sensor + Canon EF 300mm f2.8L f.7.1 1/500 ISO 200

Tornado F.3 (ZE755 'YL') with QinetiQ and operating from Boscombe Down in March 2007. 
The WSO in the back-seat has spotted me!

Left to right: Harrier GR.7A (ZD376 '24A') of 800 NAS based at RAF Cottesmore in their first week of operations after reforming in 2006, 
Typhoon T.1 (ZJ814 'QO-Z') of 3(F) Squadron in May 2008. DSLR x1.6 sensor + Canon EF 300mm f2.8L lens 1/800 at f.5.6 ISO 200 with -2/3 exposure compensation.
F-15E Strike Eagle (91-0304 'LN') callsign 'Dirty 51' of 492 FS, 48 FW at 18:14 in September 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/800 at f.3.5 ISO 200 with -2/3 exposure compensation.
C-130J Hercules (ZH883) in September 2009.

Left to right: BAE Systems Hawk 100 demonstrator (ZJ951) in July 2006. It was flying with a Hawk camera-ship down from Warton on its way to SBAC at Farnborough.
Tucano T.1 (ZF374) using callsign 'Linton 13' was continuing on to RAF Shawbury in March 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/320 at f.5 ISO 100 with -2/3 exposure compensation.
Typhoon FGR.4 (ZJ928 'QO-N') in October 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 at f.8 with -1 exposure compensation and ISO 200.
A 208 (R) Squadron Hawk T.1 in June 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/640 at f.6.3 with -2/3 exposure compensation and ISO 200.

Left to right: Uncropped image of F-15E Strike Eagle (91-0314 'LN') with stunning light and detail. DSLR x1.6 sensor + Canon EF 300mm f2.8L lens and x1.4 extender.
F-15E Strike Eagle (91-0324) of 494 FS, 48 FW. (DSLR x1.6 sensor + Canon EF 300mm f2.8L plus a x1.4 extender at 1/640 at f.8 with -2/3 exposure compensation and ISO 200). This image is a severe crop of a full frame image, however I can get away with this due to the high resolution and sharpness of the image. Keep clicking image to see full frame shot.
Tornado GR.4 (ZD810 '102') in XV Squadron markings low level through Wales in October 2008, the back-seat is studying the map. (DSLR x1.6 sensor + Canon EF 300mm f2.8L plus a x1.4 extender at 1/640 at f.7.1 with -2/3 exposure compensation and ISO 200). This is a cropped image, keep clicking image to see full frame shot.
Tornado GR.4 (ZG777 '135') in June 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 at f.8 with -2/3 exposure compensation and ISO 200.

Use the 'Crop' tool in post processing to get in close and emphasise the action.

Tornado GR.4 (ZA400 '011') still in 'Operation Telic' markings complete with 'sharks mouth' markings.

Cropping of images to A4 portrait format can make the action more dynamic.

Left to right: Tornado GR.4 (ZA597 '063') was the first of a pair in March 2007.
Anonymous Tornado GR.4 in June 2009.
Pulling 'G' Tornado GR.4 (ZG775 '134') through a Welsh valley in November 2007.
Tornado GR.4 (ZG752 '129') in September 2009.

Head-on shots. On the outside of turns and a long lens or even using the crop tool in post processing can produce some stunning head-on shots.

Left to right: Hawk T.1 (XX220) of 208(R) Squadron in June 2007, just click this image to see what a little cropping can do!
Hawk T.1W XX167) in November 2008.
Hawk T.1A (XX335) in June 2009.
Typhoon F.2 (ZJ919 'DC') in 11(F) Squadron markings in June 2007.

'Air to Air' shots at low level. At the end of valleys where they open out it is possible to get images that look like they were taken air to air.

C-130K Hercules C.3 (XV202) of Lyneham Transport Wing low flying through Wales in August 2007.
Some valleys are one sided offering panoramic backdrops to the shots to give that air to air feel.

Left to right: C-130K Hercules C.3 (XV202) of Lyneham Transport Wing low flying through Wales in August 2007.
Tornado GR.4's (ZA552 'XI' and ZG752 '129') with 13 Squadron in August 2007.
C-130J Hercules C.5 (ZH889) of 30 Squadron in December 2009 in mid Wales.

Left to right: Hawk T.1 (XX313) in 208(R) Squadron colours in November 2007.
Harrier GR.9 (ZD406 '35') in joint 800/801 Naval Air Squadron markings in November 2007.
Hawk T.1A (XX205) of 208(R) Squadron in September 2008.

Don't miss the final shot!  The going away shot at the end can make it look like the photographer is in the second aircraft of a two-ship flying in an echelon formation.

May 2007, Jaguar T.4 with after-burners, you don't get this lucky very often!
DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/640 f.4 ISO 200

Left to right: Apache AH.1 (ZJ190) of Army Air Corps 662 Squadron 3 Regiment in Wales in June 2006. DSLR x1.6 sensor + Canon EF 300mm f2.8L f.11 at 1/125.
Tornado GR.4 (ZA459 'F') in special 15(R) Squadron markings, flying from RAF Lossiemouth.
Tornado F.3 (ZE342 'DZ') when with 11(F) Squadron in 2005 and before its disbandment later in the year.
Tornado GR.1 (ZA326) in June 2005 with the ETPS shortly before it was retired. DSLR x1.6 sensor + Canon EF 300mm f2.8L lens 1/800 f5.6 ISO 200 with a x1.4 extender.

Left to right: Tornado GR.4A (ZG705 '118') with wings swept back in 13 Squadron markings with its new Tornado GR.4 fleet code '118' in August 2006.
French Air Force Alpha Jet E (E7 '314-TU') during a deployment to RAF Valley for  Exercise 'Garlic Lemon' with 208(R) Squadron in May 2008.
Tornado GR.4A (ZG729 'M') of 13 Squadron flying low through mid-Wales in March 2007.
Typhoon F.2 (ZJ922 'QO-C') of 3(F) Squadron using callsign 'Typhoon 12' in May 2008.

Left to right: Tornado GR.4 (ZG777 '135') in June 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 at f.8 with -2/3 exposure compensation and ISO 200.
Harrier GR.9 (ZD468 '58') diving in to the valley in June 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 at f.7.1 with -2/3 exposure compensation and ISO 200.
Harrier GR.9 (ZD463 '53') on its second low level sortie of the day in June 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/800 at f.7.1 with -1 stop exposure compensation and ISO 200.
Tornado GR.4 (ZG752 '129') in September 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/800 at f.6.3 with -1 stop exposure compensation and ISO 200.

Flying low in pairs is common but capturing both in the same image is not quite so easy.

Left to right: Two Tucano's entering a valley in the Lake District and two Hawk pairs from RAF Valley. 
Close formation of BAE Systems PC-9's (ZK119 'Percy' with ZG969 'Pinky') in September 2010.

Left to right: A pair of 492FS, 48FW F-15E Strike Eagles from RAF Lakenheath.
F-15E Strike Eagles (91-0324 'LN') of the 494 FS, it was followed by the 48 Wing Commanders aircraft (01-2005 'LN 48FW') in October 2008. DSLR x1.6 sensor + Canon EF 300mm f2.8L plus a x1.4 extender at 1/640 at f.5 with -2/3 exposure compensation and ISO 200.
Tornado GR.4 pair (coded '018'? and ZA370 '004') about to turn left before the Lake in June 2009.
Hawk T.1 pair (XX188 and XX315) of 19(R) Squadron and both fitted with a 30mm Aden Mk.4 Cannon packs in October 2010.

Zoom out or shoot early to capture some breath taking scenery. Just how low do they appear to fly, an elevated position and a long lens will exaggerate the low level effect?

Don't be put off from shooting towards the sun, as from your hillside you should be shooting down onto the subject and so avoiding looking directly towards the sun. With north - south running valleys it can often be beneficial to swap sides at mid-day to keep the sun behind you. In some valleys it is either not feasible to swap sides or it takes too long to do so. You can get some wonderful lighting effects if you are prepared to the places and give these shots a go. By reducing exposure compensation by up to an f-stop will help keep detail by avoiding the blown out highlights.

F-15E Strike Eagle of  494th FS, 48th FW from RAF Lakenheath, late morning in September 2004.

Left to right: 208(R) Squadron Hawk T.1 in December 2003.
1 Squadron Harrier GR.7 flying towards the sun in December 2003.
Tornado GR.4A (ZG729 'M') of 13 Squadron in June 2007.
F-15E Strike Eagle (91-0304 'LN') of 492 FW at 18:15 in September 2009, this aircraft was later to crash in Libya on March 22, 2011 during operation Odyssey Dawn to secure a no fly zone, both crew ejected safely.  DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 at f.8 with -2/3 exposure compensation and ISO 200. 

Left to right: Dominie T.1 (XS728 'E') of 55(R) Squadron and part of 3 FTS based at Cranwell in July 2006. Dominie's fly at relatively low speeds (210 knots) and are easier to photograph, but don't forget to reduce exposure to retain the detail on the white upper surfaces on bright days.
Hawk T.1A (XX303) of 19(R) Squadron shot towards the early morning sun.
F-15E Strike Eagle (96-0205 'LN') of the 492 FS, 48 FW in early morning October sun. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/640 at f.5 with -2/3 exposure compensation and ISO 200.
Tornado GR.4 (ZA602 '067') in September 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/640 at f.9 with -2/3 exposure compensation and ISO 200.

Low Cloud and Damp weather can produce some very nice atmospheric shots. Vortices or streamers emphasise speed and high-G manouvres.

F-15E Strike Eagle (98-0131) of 492 FS, 48 FW in October 2009
DSLR x1.6 sensor + Canon EF 300mm f2.8L f.2.8 -1/3 exposure compensation, 1/640 and ISO 200

Left to right: Hawk T.1's don't easily create vortices
The second of a pair of F-15E Strike Eagles (98-0133 'LN') callsign 'Jazz' of 492 FS, 48 FW circled above the 'Loop' before dropping in to my valley below the cloud that was clinging to the mountain tops in September 2009.
F-15E Strike Eagle (01-2003 'LN') was one of three pairs which dropped into the 'Loop'  at the end of a day in October 2010.  

Left to right: F-15E Strike Eagle (98-0133 'LN') callsign 'Dirty 52' of 492 FS, 48 FW from RAF Lakenheath in September 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/800 at f.4 with -2/3 exposure compensation and ISO 200.  
Harrier GR.7 (ZD466 '56') of 20(R) Squadron based at RAF Wittering on a damp 'ISO 400' day in December 2003. 'Neat Image' software was used to effectively reduce digital noise. DSLR x1.6 sensor + Canon EF 300mm f.4 L lens + x1.4 extender, 1/800 at f.4.
Tornado F.3 (ZE755 'YL') in 25(F) Squadron colours but operating out of Boscombe Down with QinetiQ, it is seen here making the tight turn through the A5 pass in September 2006.
Tornado GR.4A (ZG713 '123' 'G') it was using callsign 'Marham 79' and had a 2 Squadron code on the tail in November 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/640 at f.3.2 with -2/3 exposure compensation and ISO 200.

Snow shots a snow fall is a very nice variation to the background of low level images. Perfect conditions require combining a snow fall and decent light with being able to drive some distance with a steep hill climb at the end, is not that easy. Great care should be taken throughout.

Hawk T.1 (XX245) of 208(R) Squadron in February 2009

Left to right: Hawk T.1 (XX178) of 19(R) Squadron in December 2008. DSLR x1.6 sensor + Canon EF 300mm f2.8L plus x1.4 extender  f.11 -2/3 exposure compensation, 1/640 and ISO 200.
Typhoon T.1 (ZJ800 'BC') with 29(R) Squadron using callsign 'Typhoon 315' the pilot requested a practice diversion (PD) to RAF Valley before continuing at low level through mid-Wales in December 2008. DSLR x1.6 sensor + Canon EF 300mm f2.8L  f.10 -2/3 exposure compensation, 1/640 and ISO 200.
F-15E Strike Eagle (91-0309 'LN') of 492^nd FS using the callsign 'Strike 11' it made one high pass before returning a few minutes later at a better height for the camera in December 2008. DSLR x1.6 sensor + Canon EF 300mm f2.8L at f.5 -2/3 exposure compensation, 1/640 and ISO 200.
Hawk T.1 (XX245) of 208(R) Squadron in February 2009. DSLR x1.6 sensor + Canon EF 300mm f2.8L f.11 -1/3 exposure compensation, 1/640 and ISO 200.

Left to right: Typhoon F.2 (ZJ929 'DL') in 11 Squadron markings came through in poor weather in February 2009.
C-130K Hercules C.3A (XV303) made two passes in February 2009.
Hawk T.1 (XX256) in 19(R) markings in February 2009.
Tucano T.1's (ZF142) which came through as a pair during a snow storm in February 2009.

Use slow shutter speeds to emphasise movement the slower you go the more likely you are to have shots that go straight in to the 'bin'. I don't often go slower than 1/250th and choose common aircraft to experiment with.

Left to right: Tornado GR.4's (ZA367 '002' 'KC-N') at the 65th Anniversary of the Dambuster Raid at the Derwent reservoir on May 16, 2008. DSLR x1.6 sensor + Canon EF 300mm f2.8L f.4.5 and 1/250.
Hawk T.1 (XX187) of 208(R) Squadron in August 2011. DSLR x1.6 sensor + Canon EF 300mm f2.8L plus at f.7.1 -2/3 exposure compensation, 1/250 and ISO 250.
Hawk T.1 (XX156) of 208(R) Squadron in October 2008. DSLR x1.6 sensor + Canon EF 300mm f2.8L plus x1.4 extender at f.4 -2/3 exposure compensation, 1/250 and ISO 250.
French Air Force Alpha Jet E (E22 '705-LS') on exchange with 208(R) Squadron in June 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L at f.13, 1/160 and ISO 160.

Tornado Wing Sweep Angles

Tornado GR.4 utilising its three wing sweep angles of; 67 degrees fully swept back to 45 and 25 degrees for slow manouevres.

Warbirds at Low Level. On rare occasions its possible to capture shots that appear to go back in time.

Left to right: The Battle of Britain Memorial Flight (BBMF) at the 60th Anniversary of the Dambuster Raid, Derwent Valley May 16, 2008.
Avro Lancaster B1 (PA474) was painted in 2007 to represent one of the most famous of all Lancaster's, 'Phantom of the Ruhr'. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/250 to 1/320.
Douglas C-47 Dakota (ZA947) 'Pegasus' through the Derwent Valley on May 16, 2008.
Recently painted C-47 Dakota (ZA947) as 'kwicherbichen' (Quit your bitchin) at Derwent Valley May 15, 2011. DSLR x1.6 sensor + Canon EF 300mm f2.8L at 1/320

Left to right: Vulcan Operating Company's (TVOC) Avro Vulcan B2 (XH558/G-VLCN) appeared at the Windermere air show in July 2009.

University Air Squadron and civilian aircraft at low level. Not always the most challenging of aircraft to photograph.

Left to right: Grob Tutor T.1 (G-BYUJ) of 85(R) Squadron, Yorkshire University Air Squadron and No.2 Air Experience Flight based at RAF Church Fenton in August 2009. (DSLR x1.6 sensor + Canon EF 300mm f2.8L f.8 -2/3 exposure compensation, 1/320 and ISO 200).
Northumbrian Police Authority BN-2B-20 Islander (G-NESU) known as the 'North East Air Support Unit' in 2005.
Bulldog T.1 (XX695/G-CBBT) in the Lake District in 2006.
BAE Systems PC-9 (ZK119 'Percy') in September 2010. DSLR x1.6 sensor + Canon EF 300mm f2.8L 1/320 f.8 -2/3 exposure compensation and ISO 200.

Civilian Falcon 20EW (G-RAFR) operated Cobham (formally FRA) which is utilised by the NATO Air Forces in the air warfare training role in December 2008. (DSLR x1.6 sensor + Canon EF 300mm f2.8L f.4 -2/3 exposure compensation, 1/640 and ISO 320).
Bolkow Bo-105 (G-NAAA) operated by the Wales Air Ambulance having just recovered a person and taking him to a hospital in May 2008.
Bo-105 (G-WAAS) of the Wales Air Ambulance Service responding to a bad car crash just below us in July 2009.

Ridge running gliders. At the right location in the right weather conditions glider pilots will use the terrain to gain height and so provide great opportunities to photograph them.

Left to right: Ridge running in a 25 knot westerly with ASK 21 Glider (G-CJGJ BGA4500).

Things to consider before venturing out:

Check the weather, UK, Mountain, Wales or Cumbria.  The XCWeather website is useful fo airfield weather and winds. If the bases are not flying then the hills will be quiet.
The weather forecast should always be studied, if there is low cloud in the valleys then low level operations will be affected. The Met Office provides excellent up to date and detailed weather forecasts on the Internet.

Consult NATS-NOTAMS or NOTAMS site on occasions.
Use Street Map to find a location map in UK for an exercise location. Convert e.g. 5201N 0409W in NOTAM as; OS grid enter as x, y  N52.01,W04.09. Click minus (-) at bottom right of map for OS map.
Your valley may be closed to low flying for all or part of the day for all sorts of other reasons. Military exercises or public events can result in a 'Notice to Airmen'  (NOTAM)  being raised to prevent pilots from over-flying an area. NOTAM's and temporary Avoidance Areas ('Avoids') have been issued for all sorts of reasons, including; sheep dog trials, local low level helicopter activity and religious festivals. August can be quiet as squadrons take their annual leave. 

Other websites which may be of interest is the Ministry of Defence (MOD) site which has pages dedicated to low flying and exercises.
Wrap up warm, on the hills the weather is colder than you would expect if you are standing still all day you want to be comfortable. The weather can change very quickly.
Take walking boots, mobile phone etc.

Ordnance Survey Maps and Countryside Right of Way Act (CROW) for Countryside Access maps for England and Wales. 
Use an Ordnance Survey map to make sure you stick to the public paths. Local farmers will be easily upset if you make a nuisance of yourself on his land.
MultiMap is also useful for finding a location by grid ref or post code.

Respect the countryside, do not leave litter or leave gates open.
Be prepared to wait and wait, the first flight can be at 08:30 or even not until mid-day, if at all.
You will need typically a 300mm lens or better for full frame shots.
Good luck, it can be very rewarding.