A U.S.-based traveller is facing a mischief charge after trying to board a flight with a "mock improvised explosive device" at Toronto's Pearson airport this morning, in an incident that caused an hours-long delay for passengers. United Airlines Flight 547 was set to depart at 7 a.m. ET for O'Hare International Airport, but during security clearance, U.S. Customs and Border Protection officers found a device in a passenger's suitcase that caused them concern. According to a statement, CBP notified Canadian Air Transport Security Authority officials who "swabbed the mock IED for explosives with a negative result."