No. 4 E.F.T.S. Windsor Mills Airfield

The airfield was a temporary military installation created specifically for the British Commonwealth Air Training Plan (BCATP) during World War II. It was closed as the BCATP program was scaled down towards the end of the war, and the need for elementary flight training facilities diminished. Its closure was part of the planned decommissioning of wartime military assets.

The site of the former airfield is now almost entirely occupied by the Domtar paper mill, a massive industrial complex in Windsor, Quebec. While the original hangars and buildings are gone, the faint outline of the classic triangular runway pattern can still be discerned in satellite imagery, overlaid by industrial facilities, wood yards, and processing plants. The ICAO identifier CA-0519 is defunct and the location is no longer a registered aerodrome.

The airfield was established as Royal Canadian Air Force (RCAF) Station Windsor Mills and was home to No. 4 Elementary Flying Training School (E.F.T.S.). It opened on June 24, 1940, as a key component of the BCATP. The school was operated by a civilian company, the Windsor Mills Flying Training School Ltd., under the supervision of the RCAF. Its primary mission was to provide ab-initio (basic) flight training to thousands of aspiring pilots from Canada, Great Britain, Australia, New Zealand, and other Allied nations. Student pilots learned fundamental flying skills on trainer aircraft such as the Fleet Finch and later the Fairchild Cornell before advancing to more complex aircraft at Service Flying Training Schools. The airfield featured the standard triangular layout with three runways and numerous hangars and barracks to support the training operations.

There are no plans or prospects for reopening the airfield. The land has been completely redeveloped for heavy industrial use by the Domtar paper mill. Re-establishing an airport on this site would be logistically and economically impossible, as it would require the removal of a major, active industrial facility.