United Airlines has become the first airline to move into the Heathrow Airport's Terminal 2 after the £2.5 billion project was opened to passengers for the first time on Tuesday.
The new terminal – named The Queen's Terminal in honour of Queen Elizabeth – is part of a huge £11 billion overhaul at the airport aimed at making it one of the best in the world.
Nearly 6,000 passengers will pass through on 17 flights leaving the terminal on the first day but Terminal 2 will eventually be home to 26 airlines once they move into the new building over the next six months.
It will be honoured with a royal opening on 23 June when The Queen visits the airport accompanied by The Duke of Edinburgh.
The extension could prove favourable in the Government's eyes as it awaits Sir Howard Davies's report on the best solution to expanding UK aviation capacity.
John Holland-Kaye, Heathrow development director and chief executive designate, said: "Terminal 2 is the culmination of an £11bn investment programme that has transformed Heathrow for passengers. Opening a new terminal is one of the most complex challenges that any airport can undertake.
"Our measure of success is not everything running perfectly on day one – there will inevitably be things we can improve. Our real measure of success is whether Terminal 2 comes to be rated by passengers as one of the world's best airport terminals for years to come."