The USAAF Ninth Air Force required several temporary Advanced Landing Ground (ALG) along the channel coast prior to the June 1944 Normandy invasion to provide tactical air support for the ground forces landing in France.
Staplehurst airfield was one of the first batch of ten ALGs approved for construction which started in January 1943. All had 1 March 1943 as the target date for completion but this was too optimistic in the prevailing wet winter weather conditions and the airfield was not ready for occupation until later in the spring.
Slaplehurst consisted of two wire mesh Sommerfield Track Track runways, the main being 4,200ft aligned 10-28 and a secondary of 3.300ft at 01-19. Pierced Steel planking was also used in the construction of the hardstands and perimeter track along with several temporary hangars of wood and canvas.
Previous missions of the 363d were chiefly flown in support of Eighth Air Force heavy bomber (B-17, B-24) missions and had not fared particularly well. Its first mission from Staplehurst was also not a happy occasion as three P-51s lost in bad weather went into the sea while another crashed returning to base. Then, on 22 April four of its Mustangs failed to return and on the 29th another four were lost and yet more on 24 May.
Morale was lifted on 28 May when, in an air battle near Gardelegen, 16 enemy aircraft were claimed and 11 credited as shot down for the loss of only two P-51s and one of these was as the result of a collision with a P-47. Another seven enemy aircraft were claimed as a result of action on 30 May.
In the two weeks following D-Day, the 363rd experienced the most fruitful period of its service in the European Theater of Operations when patrols over France brought it actions with a total of 19 confirmed victories. However, a similar number of Mustangs were lost, albeit mostly to ground fire.
During operations from Staplehurst, the group was credited with 41 victories but lost 43 of its own aircraft in the process.
Another lame duck arrived on 28 June when a battle-damaged 489th Bomb Group Liberator from RAF Halesworth that put down in a hurry. Two days later, the 363rd was alerted for movement to the Continent, its new base being the airfield at Maupertus (ALG A-15), near Cherbourg.
On the continent, the 363d was reorganized into a Reconnaissance group flying the F-5 photo-reconnaissance version of the P-38 Lightning and the F-6 photo-reconnaissance version of the P-51 Mustang at Le Mans airfield, France (A-35). The 380th, 381st and 382d squadrons were redesignated as the 160th, 161st and 162d Reconnaissance Squadrons respectivley. The group flew photographic missions to support both air and ground operations; directed fighter-bombers to railway, highway, and waterway traffic, bridges, gun positions, troop concentrations, and other opportune targets; adjusted artillery fire; and took photographs to assess results of Allied bombardment operations.
It received two Belgian citations for reconnaissance activities, including the group's support of the assault on the Siegfried Line and its participation in the Battle of the Bulge (Dec 1944-Jan 945). The 363d assisted Ninth Army's drive across the Rhine and deep into Germany during the period from February 1945 to V-E Day, eventually being stationed at Wiesbaden, Germany (Y-80) at the end of hostilities in May.
The 363d returned to the United States in December 1945 and was inactivated on 11 December 1945 at Camp Kilmer, New Jersey.
When the rear party of the 363d left Staplehurst on 5 July it marked the end of the airfields use as a combat base. In September, Staplehurst was de-requisitioned and in the following month RAF works organisations removed the metal surfacing and temporary structures.