Why Do Canadian Airport Codes Begin With The Letter Y?

For anyone who’s flown, you’ll know that every airport has a unique three-letter code associated with it. From tickets to barcoded luggage tags to boarding passes, you’ll see these IATA-administered codes everywhere. A good portion of the world’s airports have airport codes that make sense in relation to their respective city or historical name. So why do Canadian airport codes begin with the letter Y? Let’s find out.

Toronto Pearson Airport.
Toronto’s Pearson International Airport is coded as YYZ. Photo: Toronto Pearson Airport

YVR (Vancouver), YYC (Calgary), YYZ (Toronto), YUL (Montreal) – all of these codes obviously begin with the letter Y. But before we get to the explanation, let’s see what most other airports are doing…

Canadians…the odd ones out

It really does seem like Canadian airports are unique in this respect. There doesn’t appear to be any other country in the world with a first-letter theme for its airport codes. On the contrary, many airports simply use a combination of letters that generally make sense with the city that an airport serves. Here are just a few examples:

  • LHR and LGW: London Heathrow and London Gatwick
  • TPE: Taoyuan International Airport serves the city of Taipei (Taiwan)
  • NRT and HND: The two airports of Narita and Haneda both serve the Tokyo Metropolitan Area in Japan
  • DAR: Julius Nyerere International Airport serves the Tanzanian city of Dar es Salaam
  • KWI: Kuwait International Airport
  • BOG: El Dorado International Airport serves the city of Bogota (Colombia)

Sometimes airport codes are more associated with the airport’s name itself and aren’t tied to the name of the cities they serve. For example:

  • CDG: Paris Charles de Gaulle
  • JFK: New York’s John F. Kennedy
  • SVO: Moscow’s Sheremetyevo International Airport
Vancouver International Airport
Vancouver International Airport is coded as YVR. Photo: Vancouver International Airport

From two letters to three

According to the Globe and Mail and its reference to an article by the Air Line Pilots Association, airlines originally copied a two-letter system used by the US National Weather Service to identify cities around the United States.

However, aviation services were growing fast in the 1930s, and towns without weather-station codes needed identification. Perhaps realizing the limits of a two-letter code, which provided only 676 combinations, it was decided that a three-letter system should be put in place. This would in turn provide a much more robust selection of 17,576 possible combinations.

Then, to ease the transition for existing two-letter-airports, some would use an X after the weather-station code. Thus, the code for Los Angeles’ airport became LAX.

Montréal-Pierre Elliott Trudeau International Airport is designated YUL. Photo: Chris Loh/Simple Flying

So ‘Y’ Canada?

According to Airfarewatchdog, in the 1930s it was important to know whether or not an airport had a weather/radio station located on its premises for safety and landing reasons. If it did, the letter Y for “yes” was added in front of the existing radio call sign. However, in the absence of a weather station at the airport, a W would be used to symbolize that it was “without” one.

Thus, when the three-letter-system was imposed during the 1940s, most of Canada’s airports had already been using the Y for “yes” prefix due to weather/radio stations located on-site. It was then decided that this should remain in place for the overwhelming majority of Canada’s airports (some begin with the letter Z).

It should be noted that while Canada has the majority of the world’s airport codes beginning with the letter Y, there are a few outside the country that also start with the same latter – for example, Yakima, Washington (YKM) and Yuma, Arizona (YUM).

So if you didn’t know the reason before, you now know the story behind Canada’s airport codes. Hopefully, that wasn’t too long of a walk to get to a somewhat short answer!

What do you think about Canada using the letter Y to begin its airport codes? Is it too much of a break from convention? Let us know in the comments.