Billy Bishop Toronto City Airport (IATA: YTZ, ICAO: CYTZ) is a regional airport located on the Toronto Islands in Toronto, Ontario, Canada. Ranked Canada's ninth busiest airport, and the sixth-busiest Canadian airport that serves the U.S. The airport is known for its location in Downtown Toronto, and the operations Hub for Porter Airlines. The airport is used for regional airline service, including transborder flights, and general aviation, including medical evacuation flights (due to its proximity to downtown hospitals), small charter flights, and private aviation. Under its operating agreement, jet aircraft are banned from the airport, with the exception of MEDEVAC flights. A proposed runway extension to accommodate small jets (CRJs and CS100s) was proposed but later canceled due to noise and safety concerns.