Britain has imposed a restriction on the airspace over London ahead of the 2012 Summer Olympic Games, which start in a fortnight with a warning that planes that stray into the zone could ultimately be shot down.
Under the Olympic air security plan, 48km of airspace surrounding the Olympic park will become a no-fly zone and general aviation will not be allowed.
Passenger planes heading for Heathrow or London City airports will not be affected.
There is also a larger restricted zone which includes Stanstead, Luton and Gatwick airports and while private pilots can enter this area, but they must submit their flight plans ahead of time.
Al Jazeera’s Laurence Lee reports from London.