What is the designator code for Thunder Bay, Ontario?

The designator code for Thunder Bay, Ontario, is indeed YQT. This code is part of the Canadian airport designator system, which assigns unique three-letter codes to airports across the country. The designator codes typically begin with the letter "Y," which is a common prefix indicating Canadian airports.

Thunder Bay International Airport is identified by the code YQT, where the "Q" and "T" distinguish it from other airports in Canada. Each airport in Canada has its own unique designator code to avoid confusion and ensure efficient air traffic operations.

The other options represent different airports in Canada: YDZ is the code for the airport serving the community of Dudzic, YTZ is for Billy Bishop Toronto City Airport, and YSJ is for Saint John Airport in New Brunswick. These codes help in identifying airports for flight plans, airport signage, and boarding passes, ensuring there's no mix-up among the various airports across Canada.