The 686 Squadron was founded on December 12, 1958. Initially, the unit was under the direction of the Frères Maristes of Dorval. The Squadron was named 686 Dorval Squadron and trained at École St-Louis-de-Marie in Dorval.

From 1960 to 1961, the training year was marked by the Cadet Exchange with the Northwest Territories Squadron. The Squadron still has the Territories flag in memory.

In 1960, the Squadron was awarded the Walsh (Military Drill Team) Trophy. The 686 has always stood out with new ideas.

In 1975, at a meeting, members of the Civil Committee asked for permission to make a name change to the Air Cadet Charter of Canada. A month later, the Squadron was named 686 Dorval-Lachine Squadron, given the large number of cadets coming from Lachine. Also in 1975, the first women were admitted to the cadet program.

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In 1981, Lachine formed the 686 Dorval-Lachine Squadron. The first commanding officer to serve was Flight Lieutenant Gérald Turcotte, with the Marists Club's Civil Committee chaired by Guy Demontigny.

In 1984, Captain Johanne Claude became the first woman to hold this position.

The year 1980-1981 was the year with no Annual Ceremonial Review (ACR) - Reason: temporary closure of the unit. That's why the Squadron has one year more in its foundation then the number of ACRs. Since its founding over 60 years ago, thousands of young men and women have answered their names at the 686 Squadron call.