RAF Bottisham opened in March 1940, when Britain was still bracing for invasion and the Battle of Britain had not yet begun. Its first occupants were de Havilland Tiger Moths - bright yellow biplane trainers - transferred from No. 22 Elementary Flying Training School and improbably fitted with bomb racks for possible anti-invasion duties. The image is hard to shake: cloth-and-wood trainers, designed to teach novices, equipped to dive on German landing craft. From October 1940 the Tiger Moths used Bottisham as a Relief Landing Ground. When they left in 1941, the airfield passed through a succession of RAF squadrons flying Lysanders, Tomahawks, Mustang Mk I's, Hurricanes, Defiants, and Spitfires - a roll call of early-war British air power.

On 30 November 1943 the United States Army Air Forces Eighth Air Force 361st Fighter Group arrived from Richmond Army Air Field, Virginia, and Bottisham became American. The group was assigned to the 65th Fighter Wing of VIII Fighter Command and identified by yellow paint around its cowlings and tails. Three squadrons made up the group: the 374th, 375th, and 376th. The 361st entered combat with Republic P-47 Thunderbolts on 21 January 1944 and converted to North American P-51 Mustangs in May 1944. The Mustangs were what the bomber crews had been praying for: long-legged fighters that could escort B-17s and B-24s all the way to their targets in Germany and bring them home.

The 361st flew through some of the war's most consequential weeks. It took part in Big Week, the all-out assault on the German aircraft industry from 20 to 25 February 1944. It covered the Normandy invasion in June and the Saint-Lo breakthrough in July. Between escort missions, it ran counter-air patrols, fighter sweeps, and strafing and dive-bombing runs against airfields, marshalling yards, missile sites, ordnance depots, oil refineries, trains, and highways. The weight of the heavy P-47 fighters had been telling on the wet Cambridgeshire grass. In January 1944, an American engineering team laid a 1,470-yard runway of pierced-steel planking in three days - a record for prefabricated runway construction. The PSP runway, aligned northeast to southwest, became Bottisham's main.

In September 1944 the 361st moved to RAF Little Walden, a Class A airfield with concrete runways and much better facilities than Bottisham's PSP and Nissen huts. From mid-1945 until 5 January 1946, Bottisham was used temporarily by Belgian airmen before closing. The land was returned to agriculture. Today, the outline of the PSP runway can still be seen from the air as that long thick row of trees, with the wartime intersecting track now a permanent road cutting through the trees at the southwest end. The Bottisham Airfield Museum opened in 2009 in the last remaining buildings on the original perimeter - the only UK museum dedicated to the RAF, the United States 8th Army Air Force, and the Belgian Air Forces. The site purchase was completed in September 2014, and restoration has continued steadily since. A new Nissen hut has been installed in the original position of one that stood there in 1944.