The Bismarck airport was evacuated late this afternoon and planes on the tarmac were grounded.
A passenger who flew in from Minneapolis sat in the plane on the tarmac for an hour and half before the passengers were let onto the tarmac.
Passengers were not allowed to go into the airport, however they were allowed to walk out and leave.
Lines of cars are incredibly long at the airport as people are allowed to leave, but no one is allowed in.
KX News is continuing to follow this developing story.