Operation Yellow Ribbon

Operation Yellow Ribbon (French: Opération ruban jaune) was commenced by Canada to handle the diversion of civilian airline flights in response to the September 11 attacks in 2001 on the United States. Canada's goal was to ensure that potentially destructive air traffic be removed from United States airspace as quickly as possible, and away from potential U.S. targets, and instead place these aircraft on the ground in Canada, at military and civilian airports in the Canadian provinces of Nova Scotia, Newfoundland and Labrador, and British Columbia (and also several in New Brunswick, Alberta, Manitoba, Ontario and Quebec) where any destructive potential could be better contained and neutralized. None of the aircraft proved to be a threat, and Canada and Canadians hosted thousands of passengers stranded in Canada until U.S. airspace was reopened.

Canada commenced the operation after the U.S. Federal Aviation Administration (FAA), implementing Security Control of Air Traffic and Air Navigation Aids (SCATANA), grounded all aircraft across the United States, an unprecedented action. The FAA then worked with Transport Canada to reroute incoming international flights to airports in Canada.

During the operation, departing flights—with the exception of police, military, and humanitarian flights—were cancelled, marking the first time that Canadian airspace had been shut down. In total, as a result of Operation Yellow Ribbon, 255 aircraft were diverted to 17 different airports across the country.

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Wikipedia