On April 1, 1947, 438 Squadron regained its wartime designation as 438 (Fighter) Squadron in preparation for its soon-to-arrive new aircraft. The Wildcats became one of the first units to become operational on jet fighters when they begin operations on the British designed and built de Havilland Vampire in April 1948. 1949, The Wildcats of 438 Squadron, alongside their colleagues of 401 Squadron also on Vampires, participated in OP METROPOLIS, a large scale joint USAF/RCAF air exercise where the 2 RCAF jet fighter squadrons, with the assistance of No.1 RCAF mobile radar unit were to defend the greater New York area from bomber formations composed of American B-26 bomber squadrons.