Passenger Steve Allen said: "I was reading my newspaper and the young lady in question who was sat two seats away from me began to make some moaning noises.
"I wonder what was going on and we suddenly all realised she was having contractions."
He added: "It was quite exciting actually, usually everyone reads their newspaper and sits there not saying anything but suddenly we had this fantastic thing happening.
"It was like Christmas."
what else is like Christmas?