When the invasion of Belgium and the Low Countries was launched on the 10th. May 1940, the allies were in no position to defend themselves, and the Belgian Air Force was virtually destroyed on the ground within the first few hours of the onslaught.

However, on the 11th. May a Belgian force of nine Fairey Battle bombers, escorted by six Gloster Gladiator fighters attacked three bridges over the Albert Canal. Of this gallant force, only three Battles and two Gladiators returned.
After the cease-fire in Belgium on 28th May 1940, what was left of the Belgian force moved to France, where it was intended that they continue the fight alongside the French air force.

However, when France capitulated in June 1940, several pilots escaped to the United Kingdom, where with the agreement of the Belgian embassy, they were integrated into the Royal Air Force. Thus twenty nine Belgian pilots took part in the Battle of Britain, seven of who lost their lives .

In June 1942, following the escape of the Belgian government to exile in London, agreement was reached to integrate all Belgian air and ground crews into the RAF, and to form Belgian "Flights" within No's 609 and 131 squadrons.
Later in the war, once enough Belgian personnel had been trained, it was agreed to raise "Belgian" squadrons, as a result of which No's 349 and 350 squadrons were formed.

Throughout the war years Belgians could be found not only in these Belgian 'Flights' and squadrons, but throughout the RAF and in all campaigns, especially with Bomber and Coastal Commands and between June 1940 and May 1945, approximately 520 Belgian officers flew with the RAF, of whom 128 were killed in action.