Passengers Stranded in Hot Plane for 3 Hours at Philadelphia Airport

— -- A mechanical issue left more than 150 passengers stranded on a taxiway at Philadelphia International Airport for nearly three hours Monday night, Frontier Airlines confirmed to ABC.

After shutting off the engines to conserve fuel while waiting for de-icing, the pilot -- slated to fly from Philadelphia to Tampa -- was unable to re-start the plane.

He reportedly told passengers the problem with the auxiliary power unit had also wiped out the jet’s heating and air conditioning systems, leaving travelers stuck on a plane with “no air, no circulation and a screaming baby,” according to passenger Shana Laura.

“I was really trying to keep myself calm,” said Laura, who is pregnant with her first child. “You started feeling like you couldn’t breathe.... I was on the verge of hyperventilating.”

The plane sat on the tarmac "just shy of three hours," before being towed to the gate, Frontier said. The airline attributed the delay to a “lack of gate space because of other diversions” at the airport.

(Regulations prohibit airlines from keeping passengers inside planes on the tarmac for more than three hours unless there are security concerns or air traffic control "advises the pilot that returning to the terminal would disrupt airport operations," according to the Department of Transportation.)

According to Laura, flight attendants made the rounds with a beverage cart just once and instructed passengers that they shouldn’t leave their seats to use the bathroom.

The flight was eventually cancelled.

When passengers returned to the gate just before midnight, they were eventually offered hotel vouchers -- for a hotel that they would later learn was already fully booked. Many of those that didn't have anywhere to go holed up at the airport for the night, the airline confirmed.

Frontier eventually offered passengers refunds and travel vouchers and said it was bringing in a plane to fly passengers to Tampa this afternoon.