Multiple Canadian airports faced bomb threats Thursday morning that grounded flights and are expected to cause widespread delays, according to air traffic control manager Nav Canada."Early this morning,

A series of bomb threats that briefly grounded flights at six major Canadian airports Thursday began with an early morning phone call to an air traffic control tower in Vancouver, soon repeated at other towers across the country.

Major Canadian airports are returning to normal operations after they were forced to delay some morning flights on Thursday because of bomb threats.The threats affected facilities in Ottawa, Montreal,