When booking a flight for your dream vacation, you may have noticed that almost every airport code in Canada begins with a "Y" — the most curious letter in the alphabet. When booking a flight for your dream vacation, you may have noticed that almost every airport code in Canada begins with a "Y" — the most curious letter in the alphabet. A flight from Montreal to Toronto becomes "YUL to YYZ," Edmonton to Saskatoon is marked "YEG to YXE," and Vancouver to Ottawa shows "YVR to YOW." Historical records do not indicate a ouija board or alphabet soup factory explosion involved in the confusing code selection. It actually all dates back a century to when airport codes across North America were just two letters and Morse code featured in airline navigation.