An airline is investigating claims a stewardess panicked as her flight hit turbulence and repeatedly screamed: "We're going to crash".

Passenger Paul Gibson, 30, from Eastbourne, was on Virgin Atlantic's flight VS43 from Gatwick to Las Vegas when it hit a patch of severe turbulence three hours into the flight.

The Boeing 747-400 aircraft, carrying 451 passengers and 18 crew, dropped from 38,000ft to 30,000ft in a matter of seconds.

Mr Gibson, editor of the Eastbourne-based trade publication Chauffeur Magazine, was on board travelling to a limousine convention in Las Vegas.

He said: "She began screaming every time the plane shook. She shouted at the top of her voice, 'We're going to crash, we're going to crash, we're going to crash'."

Mr Gibson said the stewardess was tossing sick bags towards terrified passengers.

He said: "She grabbed a box and threw them across the plane. There were about five people around me throwing up. I fly a lot and I have never experienced anything like it in my life."

Another passenger, Claire Daley, 34, from Stone, Staffordshire, said: "Outside we could see the wing was bent right up by the force. I looked to the stewardess for reassurance but she let out a large scream.

"At that, all the other passengers screamed too. I just thought, it's over. If an air hostess is telling us we are crashing, I really thought we were."

Mr Gibson said one passenger, who was not wearing a seatbelt, was thrown into an overhead locker and others were crying and praying or clinging to the floor.

He said: "The turbulence started very suddenly and one member of cabin crew said it was the worst they had experienced in seven years of flying.

"Passengers who were walking about the aircraft had to sit on the floor and hold on."

Virgin Atlantic, which is based in Crawley, is investigating the claims but a spokeswoman said so far none of the passengers had lodged complaints about the stewardess.

She said: "The safety and security of passengers and crew is Virgin Atlantic's top priority.

"The flight deck will always keep passengers informed of expected flying conditions and where possible will try to avoid areas of expected turbulence.

"Incidents of unexpected turbulence are relatively rare but as a precaution passengers are always advised to wear seatbelts at all times during the flight."