Passengers trying to take control of the plane and land it? That's the most logical explanation.
BUT
I'm thinking they would have radioed the tower or signaled to the F-16's.
Very strange, getting into 'Twilight Zone' territory.
But the article SAID that a flight attendant's body was found in thje cockpit. So she was probably trying desperately to land the plane somehow. Assuming she was also the one who was found to be alive at the time of the crash.