Canadian travellers, airlines, and airports could be hit with financial setbacks if U.S. pre-clearance services are withdrawn from Canadian airports, according to aviation experts.

U.S. Ambassador to Canada Pete Hoekstra revealed that pre-clearance facilities—where travellers undergo U.S. customs and immigration checks before boarding flights—are facing declining use as cross-border travel has slowed this year. Speaking at the Global Business Forum in Banff, Alberta, Hoekstra suggested Washington may reconsider the program.

“We’re not sure we can make the numbers work anymore … pre-clearance is something that is done at the expense of the U.S. government. We paid for it,” the ambassador said.

Ending the service could increase costs for major airlines and airports while creating longer delays for passengers, experts caution.