The FBI worked with Dallas/Fort Worth International Airport Public Safety after a bomb threat was made on an United Express flight from California.
United Express flight 5394 originated at Los Angeles International Airport and landed at DFW at about 3 p.m. Friday.
The regional jet operated by SkyWest Airlines was immediately moved to an isolated area on the far west side of the airfield.
"Clearly in a situation like this one, we’re going to take it seriously and we're going to respond as quickly as we can with as many assets as we have," DFW Airport spokesman David Magana said.
The 66 people on board, including 62 passengers and four crew members, safely got off the plane.
"Whatever it was initially, they made sure we knew it was serious and not to be taken lightly," passenger Walter Wooden said.
The FBI confirmed that a handwritten bomb threat was discovered in the bathroom of the plane.
"I asked a flight attendant point blank, 'What's going on?' and she had just told us that someone had written on the bathroom mirror that there was a bomb on board or that there was a potential threat," said passenger Cherylyn Witsell, of Frisco. "She didn't say there was a bomb on board, she said there was a threat that they were taking seriously, and someone else told me that someone had written that on the mirror."
The FBI and DFW police finished interviewing the passengers and crew at about 6:30 p.m. After they were interviewed, the passengers were returned to Terminal E Gate 2.
"We all got questioned," passenger Pat Hopkins said. "They wanted to know who we were, where we live if we had any gripes with the airline."
Meanwhile, DFW's Explosives Ordnance Detection Unit and DFW canine units completed an inspection of all of the baggage from the aircraft as well as the jet at about 4:50 p.m. The jet was cleared and returned to Terminal E where the Transportation Security Administration conducted another sweep of the plane.
Nothing was found and the jet was returned to service.
Runway 13R was closed for nearly two hours, but there was no other affect on flight operations at DFW. No flights were delayed or canceled.
NBC 5's Ellen Goldberg contributed to this report.