United States border preclearance is the United States Department of Homeland Security's (DHS) practice of operating prescreening border control facilities at airports and other ports of departure located outside of the United States pursuant to agreements between the United States and host countries. Travelers are subject to immigration and customs inspections by Customs and Border Protection (CBP) officers before boarding their transportation onward to the United States. Preclearance applies to all passengers regardless of their nationality or purpose of travel. Upon arrival, precleared passengers arrive in the United States as domestic travelers, but may still be subject to re-inspection at the discretion of CBP. This process is intended to streamline border procedures, reduce congestion at American ports of entry, and facilitate travel into airports that otherwise lack immigration and customs processing facilities for commercial flights.

Ottawa/Macdonald–Cartier International Airport is the main international airport serving Ottawa, Ontario, Canada, and its metropolitan area as well as Gatineau, Quebec known as the National Capital Region. It is named after the Canadian statesmen and two of the "founding fathers of Canada", Sir John A. Macdonald and Sir George-Étienne Cartier. Located 5.5 nautical miles south of downtown Ottawa in the south end of the city, it is Canada's sixth-busiest airport, Ontario's second-busiest airport by airline passenger traffic, with 4,095,914 passengers in 2023. The airport is a home base for Canadian North and a hub for Porter Airlines.