"Y" is used because:
When formal radio regulations began, radio call signs were assigned to each country in the world. Canada was assigned the following first two letters: CB, CF, CH, CI, CJ, CK, CY, CZ. Newfoundland was assigned VO. When they joined Canada, these letters joined Canada with them. Canada chose to use CB for CBC broadcasting (the Canadian Broadcasting Corporation). CF, CH, CI, CJ, CK was used for other broadcasters. CY, CZ was used for transportation communication. That's why Canadian airports start mostly with CY - or - just "Y" if you drop the "C". Hope this clears things up a little. Find out what letters were assigned to your countries. That would be interesting.