According to one of the passengers, the aircraft's cabin crew said two men had repeatedly tried to get into the cockpit.
Umari Nauman told Sky News: "The cabin crew informed us that basically they tried to come into the cockpit a few times and because they had been asked not to do that they got into a bit of an argument with the crew and made a few threats."
She said all the passengers had been ordered to leave their possessions on board before leaving the plane.
Ms Nauman also said helicopters escorted the aircraft before landing.
More top news
As people across London celebrate Christmas, Micah Community Church share their Christian beliefs of the special day.
Police are now investigating the 'unexplained' death of a 23 year old man from Erith who was found dead in June.
Most of the squatters who took over the former RBS HQ on Trafalgar Square to feed homeless people on Christmas day have been evicted.