Ummm actually 3 letter Canadian codes can start with X Y or Z
Bathurst NB (ZBF) springs to mind as a Z designator, but Y is by far the most prevalent, and FYI, its not just airports that have designators, VORs have the same series.
for the 4 letter codes, all Canadian airports start with C
CYYZ, CYYC, CYVR, CZBF, and so on, just like all US airports are Kxxx designated. However there are certain requirements for an airport to receive a Cxxx code, all of which are satisfied anyways for the airport to be opened to commercial traffic, if the airport doesnt meet these requirements it gets a random alpha-numeric designator something like 00BV.
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