Heathrow reported higher revenues and profits after a record 70m passengers used Britain's biggest airport during 2012.
It posted an 8% rise in revenues to £2.46bn, while it returned to the black with profits of £46.4m.
But the airport is operating at near capacity and the company warned this would limit the UK's ability to trade with emerging economies. There were 471,341 flights in 2012, just below its cap of 480,000 a year. The results from the former BAA company include Stansted Airport, sold after year-end for £1.5bn.