RAF Dundonald opened in March 1940, not as a frontline station but as a relief landing ground for nearby RAF Prestwick. Prestwick was home to No. 12 Elementary Flying Training School, and Dundonald gave its student pilots somewhere quieter to practise circuits and bumps in de Havilland Tiger Moths. Two short grass runways were enough at first, though later they were reinforced with Sommerfeld Tracking, a rolled mesh of wire and steel rods that turned soft ground into something an aircraft could actually use in rain. There were no hangars to speak of, no elaborate buildings, just the bare minimum required to teach young men how to take off, land, and try again. When 12 EFTS was disbanded in March 1941, Dundonald fell quiet.

Then came one of the war's strangest episodes. On the night of 10 May 1941, Rudolf Hess, Hitler's deputy, parachuted into Scotland. Author John Harris has argued there is evidence Dundonald may have been Hess's intended destination, with high-ranking officials waiting to negotiate as part of a plot involving the king proroguing parliament and threatening to remove Churchill. Constitutionally, Harris notes, this was possible. An alternative theory casts the whole thing as an MI6 ruse to lure Hess from Hitler's orbit and clear the way for Martin Bormann. Both readings are speculative, and both flatter a sleepy Ayrshire airfield with a role it may never have played. What is certain is that Hess bailed out short of any planned destination and landed in a field near Eaglesham. Whatever Dundonald's role in the conspiracy theories, the airfield itself slept on.

Dundonald's real wartime purpose arrived in April 1943, when 516 (Combined Operations) Squadron formed at the airfield. Its job was to make commando training feel real. Pilots flew a mixed inventory of aircraft: North American Mustangs and Hawker Hurricanes as fighter-bombers, with Bristol Blenheims, Westland Lysanders, Avro Ansons and Percival Proctors filling other roles. They simulated air attacks on assault troops scrambling up Ayrshire beaches, smoked targets, dragged drogues for gunnery practice, and pretended to be enemy aircraft long enough that the men learning to dodge them would not freeze when the real thing came at low level over Normandy. Detachments from other RAF and Fleet Air Arm squadrons also rotated through. Once the success of the Normandy landings made the training programme unnecessary, 516 Squadron was disbanded in December 1944. RAF Dundonald went onto care and maintenance, closed in August 1945, and was retained by the army until 1952.

In the 1960s a Monsanto nylon plant rose on part of the site, prosperous enough at first but closed by 1979. The land was redeveloped as Olympic Business Park, and the rest of the airfield reverted to farmland. None of the temporary wartime buildings survive. There is no preserved control tower, no plaque you can drive to without going looking. The squadrons that trained here, including detachments from 2, 18, 26, 63, 268, and the Canadian 414 Squadron RCAF, along with 808 Naval Air Squadron, are remembered chiefly in unit histories and combined-operations records. What Dundonald left behind is more abstract: the men who came ashore at Sword and Gold and Juno had been trained somewhere, by aircraft that had to be flown somewhere, and a great many of them learned the rhythm of it here, on grass strips above the Ayrshire coast.