Update - Nov 16 at 1.15am: An Oklahoma airport has resumed operations after a suspect in a fatal shooting was found dead in a parking garage.
Will Rogers World Airport in Oklahoma City was shut down by police shortly after a Southwest Airlines employee was shot about 1pm local time on Tuesday.
Michael Winchester, aged 52, died after being taken to hospital following the shooting and a suspect was later found dead in a pick-up truck in an airport parking garage.
Police and airport spokeswoman Karen Carney said the airport has now resumed operations.
Hundreds of people were kept inside the airport terminal for hours after the shooting and Ms Carney said about 25 flights were cancelled, most of those by Southwest Airlines, which cancelled all flights scheduled to depart Oklahoma City for the remainder of the day.
Earlier: The Oklahoma City airport has been closed after a person was shot, with police searching for a possible second victim.
The Oklahoma City Police's Twitter account said the Will Rogers World Airport was closed following the Tuesday afternoon shooting and anyone inside should "shelter in place".
Police Captain Paco Balderrama said officers have confirmed one victim, adding that police received reports of a possible second victim, but authorities have not yet found that person.
He said he does not know the condition of the confirmed victim.
Mr Balderrama said all streets are blocked off and people should avoid the airport.
Airport spokeswoman Karen Carney said all operations are suspended.
She added that 7,000 to 8,000 travellers go through the airport daily.