A pilot told them two of the cockpit screens suddenly went blank mid-flight.
One of the passengers recorded video of the pilot making an announcement over the loudspeaker telling them what happened.
"You may be able to see we lost two of our screens. Now if we kept flying, we'd lose them all. There is tremendous heat behind those screens," the pilot is heard saying.
The pilot said they needed to land immediately or he'd be "flying blind" if they continued.
United 4390 lost their screens in the cockpit pic.twitter.com/vliOVotLWW— Rodney D. Giles (@rodneygiles) April 5, 2019
The flight was headed to Houston from Knoxville, Tennessee, Thursday night when it suffered mechanical issues. It was diverted to Dallas before landing at Bush Airport.