Airport screening refers to the security checks passengers and baggage undergo before boarding flights. In Canada, the Canadian Air Transport Security Authority (CATSA), a federal Crown corporation, conducts screening at all major airports. This includes X-ray scanning of carry-on bags, metal detectors or body scanners for passengers, and random checks for explosives. Screening standards are set by Transport Canada based on international requirements. While airports are physically located in municipalities, security is entirely a federal responsibility—one reason why airport security remained consistent across Canada even during provincial emergencies. CATSA's budget comes from federal appropriations and fees charged on airline tickets, not from municipal taxes.