Outside of World War III it's going to be tough but here's one possible way I see it happening.
1. During the post-war period Kurt Tank begins to try and negotiate with various countries for his services these included the UK, the USSR, and eventually his final destination Argentina. Let's say in TTL Roy Dobson (the founder of Avro) gets wind of this and convinces the UK to accept Tank's offer. Tank and perhaps a few more German engineers and people with expertise make their way to Canada where they begin working on the RCAF's 1946 requirement for an all-weather fighter. This results in TTL's version of the CF-100 Canuck being produced much earlier (perhaps with a slightly different design? Swept wings etc.) and in time for the Korean War.
In addition to the CF-100 being produced by the USAF for the Korean War, Canada sends a fighter unit over to Korea where they see some action. One pilot manages to get the jump on a couple of MiG's and racks up some of Canada's first post-war kills.
2. Then a more conservative government gets Canada involved in Vietnam where the same veterans from Korea rack up some more kills making one of them a RCAF ace.