A record 70 million passengers used Heathrow last year, boosting the airport's revenues by 8% to £2.46bn.
The airport, the UK's busiest, is operating at close to capacity, with 471,341 flights during 2012, just below the legal limit of 480,000 a year.
Passenger numbers fell by 400,000 during the Olympics, as Britons stayed home to enjoy the Games and the number of inward-bound travellers dipped.
The chief executive of Heathrow again warned about a lack of capacity.
Colin Matthews said a decision on new airport capacity was "urgent", because of competition from rival airports in Europe and the Middle East.
The results published on Monday include Stansted airport, which was sold to Manchester Airports Group for £1.5bn. Stansted's passenger numbers fell 3.2% to 17.5 million last year.
The company said construction of the new Heathrow Terminal 2 should be completed towards the end of 2013, with operations commencing in mid-2014.
The project accounted for a large slice of the £1.1bn invested in the airport during 2012, an increase of more than 30% on a year earlier.