Negotiations between Spirit Airlines and its pilots entered their final stage on Friday, with pilots threatening to walk out at midnight if they don't get a new contract.

"We're still in negotiations, and we still hope to reach a deal, but we still have a lot of work to do," said Arthur Luby, assistant director of representation for the Air Line Pilots Association.

The company has also said it hopes to make a deal, and strike threats are a common feature of the endgame of airline negotiations.

Still, a pilot strike at Spirit could disrupt the travel plans for thousands of passengers. The airline canceled some flights in advance.

Cousins Greg Watson, 44, and Doug Ferraro, 43, were among the passengers affected by the cancellations. They made it from Tampa, Fla., to Spirit's hub in Fort Lauderdale, only to find that the next leg of their vacation to the Bahamas was canceled.

"We didn't even get a phone call - we showed up and they said they had no pilots," Watson said. "They don't have any back-up plan. This is the most disorganized thing I've ever seen - it's ridiculous."

They were given $75 to take a taxi to the Miami airport so they could try to catch a flight from there. They said they would never fly Spirit again.

"I've already got someone working on a nasty letter," Ferraro said.

Spirit pilots have said their pay lags that of competitors like JetBlue Airways Corp. and AirTran Airlines, part of AirTran Holdings Inc.

"We are looking for pay parity," said Sean Creed, a Spirit captain and the head of the Air Line Pilots Association unit there, in a recent interview. "We're not looking to be industry leading," he said. "We're not looking to place the company at an economic disadvantage."

Negotiations were being conducted in Washington and directed by the National Mediation Board. If there's no deal, pilots could strike as early as 12:01 a.m. EDT Saturday. The president can halt an airline strike, but that was considered unlikely because of Spirit's small size. It runs roughly 150 flights per day, compared to 6,200 for Delta Air Lines Inc., the world's largest carrier.