First airmail service in Canada from Montreal to Toronto.

Airmail is a mail transport service branded and sold on the basis of at least one leg of its journey being by air. Airmail items typically arrive more quickly than surface mail, and usually cost more to send. Airmail may be the only option for sending mail to some destinations, such as overseas, if the mail cannot wait the time it would take to arrive by ship, sometimes weeks. The Universal Postal Union adopted comprehensive rules for airmail at its 1929 Postal Union Congress in London. Since the official language of the Universal Postal Union is French, airmail items worldwide are often marked Par avion, literally: "by airplane".

Montreal is the largest city in the province of Quebec, the second-largest in Canada, and the ninth-largest in North America. It was founded in 1642 as Ville-Marie, or "City of Mary", and is now named after Mount Royal, the triple-peaked mountain around which the early settlement was built. The city is centred on the Island of Montreal and a few, much smaller, peripheral islands, the largest of which is Île Bizard. The city is 196 km (122 mi) east of the national capital, Ottawa, and 258 km (160 mi) southwest of the provincial capital, Quebec City.

Toronto is the most populous city in Canada and the capital city of the Canadian province of Ontario. With a population of 2,794,356 in 2021, it is the fourth-most populous city in North America. The city is the anchor of the Golden Horseshoe, an urban agglomeration of 9,765,188 people surrounding the western end of Lake Ontario, while the Greater Toronto Area proper had a 2021 population of 6,712,341. As of 2024, the Golden Horseshoe had an estimated population of 11,139,265 people while the census metropolitan area had an estimated population of 7,106,379. Toronto is an international centre of business, finance, arts, sports, and culture, and is recognized as one of the most multicultural and cosmopolitan cities in the world.