The three options put forward on Wednesday will allow the airport to move from 480,000 flights a year to 740,000. Each of the plans will mean some compulsory property purchases and major work on a key London highway.
But Heathrow executives backed away from immediately proposing a fourth runway - an idea floated by planners concerned that a lack of airport capacity could hurt Britain's competitiveness.
Expansion at Heathrow has been controversial, as residents have complained about the noise and pollution.
London's Mayor Boris Johnson has put forward other alternatives, and a commission will rule on which is best.