The passenger locked himself in a lavatory. The plane landed safely at approximately 12:00 noon local time and the passenger in question is in custody.
NORAD confirms it scrambled two F-16s in response.
The incident comes two days after two F-15 fighter jets escorted aback to Portland International Airport after a passenger became disruptive Wednesday afternoon.
Hawaiian Airlines flight 39 from Portland to Kahului Airport in Maui returned to Portland after a passenger made threatening remarks and refused to store his carry-on bag.