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.

Toronto Pearson International Airport is an international airport located in Mississauga, Ontario, Canada. It is the main airport serving Toronto, its metropolitan area, and the surrounding region known as the Golden Horseshoe. The airport is named in honour of Lester B. Pearson, who served as the 14th Prime Minister of Canada (1963–1968) and received the Nobel Peace Prize in 1957 for his humanitarian work in peacekeeping.