Edinburgh Flying Club began using Macmerry aerodrome, which was sometimes referred to as Tranent or Penston, in 1929. In this photo scouts from Tranent are seen during their visit to the field in 1938, which evidently included some instruction in the use of gas masks, a quite startling sign of the approaching world war. Nevertheless, this was still peacetime and from 1936 to 1939 North Eastern Airways operated some scheduled flights from Macmerry.
The landing ground was taken over by the Royal Air Force in 1941 and on 16 January a detachment of Hurricanes from No. 607 Squadron moved to Macmerry, rejoining the rest of the squadron at Drem on 2 March. Three days later, on 5 March 1941, No. 614 (County of Glamorgan) moved into Macmerry from Grangemouth, flying mainly Westland Lysanders and Bristol Blenheims, although there were also a number of miscellaneous types. One such was the de Havilland 89A Dominie, the military versions of the de Havilland Dragon Rapide light airliner, which was used for a variety of communications duties. No. 614 Squadron was an Army Co-operation squadron, carrying out such work as spotting for artillery units, reporting on any necessary corrections in the range and direction of the shelling, as well as general reconnaissance and even light bombing duties. At Macmerry, however, these duties were only training exercises, and it was only when detachments were sent south that squadron members were able to put their training to use.
At the end of May 1942 eight Blenheims from 614 Squadron were detached to West Raynham in Norfolk to carry out intruder attacks on Luftwaffe night fighter airfields in support of the 1000 bomber raid on Cologne on the night of 30/31 May 1942, the Blenheims returning to Macmerry soon after. Part of the squadron was again detached from Macmerry, in August 1942, to participate in the raid on Dieppe on 19 August.
In 1942 No. 614 Squadron was joined at Macmerry by several other Army Co-operation units. No. 13 Squadron was here for the first ten days of August 1942 with its Blenheims and No. 225 Squadron arrived on the last day of August for two months with Mustangs before heading off for North Africa. On 21 November 1942 No. 63 Squadron found itself, with its Mustang aircraft, at Macmerry until moving to Turnhouse in July 1943, although a detachment remained at Macmerry for a few weeks. These units were involved in a number of local army exercises such as Exercise Dryshod which was held in early August 1942 in Ayrshire, a rehearsal for the landings at Dieppe which took place only a few days later. No. 13 Squadron was amongst the units which provided air support for the troops involved in the mock amphibious landing. During 1942 Macmerry aerodrome was greatly expanded in size, extending onto the site of the First World War landing ground at Penston, used by No. 77 Squadron from 1916 until being disbanded in 1919.
A great many other units used Macmerry at various times during the war. The Operational Training Units at East Fortune used Macmerry as a satellite station. From the beginning of 1943 the R.A.F. Regiment had a training school at Macmerry and from October 1943 to early 1944, 200 U.S. Army Air Force ground staff were based here, as was an Elementary Gliding School between April 1944 and 1946. Cunliffe-Owen Aircraft Limited had a factory on the aerodrome, the workforce of which were principally concerned with the repair of Lockheed Hudson aircraft. Macmerry aerodrome also played an important apart in the deception operations intended to make the German High Command believe that there was an invasion of Norway planned from Scotland (see Operation Fortitude North).
On 21 April 1945 Macmerry was loaned by the R.A.F. to the Royal Navy, the intention being that No. 770 Squadron, Fleet Air Arm would use the aerodrome, although this did not happen. However, Macmerry was commissioned on 1 June 1945 as a satellite of Drem which was already being used by the Fleet Air Arm, Macmerry being allocated the name H.M.S. Nighthawk II. However, Macmerry was never actually used by the Fleet Air Arm and was returned to the R.A.F. on 15 March 1946.
Macmerry was reopened by the Edinburgh Flying Club on 31 August 1946, having gone full circle from its pre-war use, and flying from here finally ended with the closure of the airfield in 1953.