Montréal's Trudeau International Airport (also often referred to by its previous name, Dorval) is about 24 km (15 miles) west of the city center.
The easiest way to get in is to take a cab for a fixed fare of C$38 or a limousine for about C$55, unless your hotel provides transportation. The cheapest way to get into town is the 747 express bus, a 24-hour shuttle service from the airport to the main bus terminal with stops at the Lionel-Groulx métro station and several additional stops near Downtown hotels. The fare is C$9 one-way—with 24 hours of unlimited bus and métro travel included in the price. Plan on it taking about a half hour outside rush hour to get to Downtown from the airport.