War had broken out in Europe and the Newfoundland Government, to provide for more security in time of war, wanted Canada to take military control over the Newfoundland Airport. But the British Government objected. It was only after there were changes in the development of the war did the British relent and give this idea their blessing.
The first RCAF aircraft, a detachment of 10 (BR) Digbys, arrived in June 1940, but the RCAF didn't assume control until April 1941 (and only then after lengthy discussion and formal agreement with the Commission of Govt). It also notes that the RCAF's role was to maintain and manage the airport. However, the RCAF played an important role in the Battle of the Atlantic with Gander-based squadrons carrying out antisubmarine patrols and convoy escort work, while Hurricane fighter squadrons protected the base and trained in preparation for transfer overseas.
During this era because of the airport's importance in it's strategic location, the original development was improved upon. The RCAF were later joined by the Canadian army, the RAF and the US Army/Airforce. Civilians were needed to provide support for the military and the construction of their bases. They were recruited across Newfoundland. Families were not permitted, it was singles only.
Each military unit had a role to play. The RAF and US Army/Airforce dealt with the transporting of military aircraft. The Canadian Army looked after security. The RCAF maintained and managed the airport itself.
The airport was renamed Gander Airport and now became the North American jump off point for the supply of military aircraft to the war effort in Europe.