Travellers could be paying £1.2 billion more in air fares by 2030 if there is no airport expansion, an aviation regulation chief told MPs today.
Capacity problems at airports was already leading to increased fare prices, Civil Aviation Authority (CAA) chief executive Andrew Haines told the House of Commons Transport Committee.
All three main London airports (Heathrow, Gatwick and Stansted) were capacity constrained at peak hours, he told MPs.
"We believe at peak hours passengers are paying more than they would if there was more capacity," Mr Haines told the committee.
He said that although he would like to see a major hub airport in future UK aviation plans, it was important not to put "all the eggs in one basket".
Mr Haines said that demand for air travel was "peaky", in that there was a peak in south east England and there was a peak at certain times of the day.
"Shifting people away from these peak times, despite attractive fare pricing, is not working," he added.
MPs asked about the so-called "Boris Island" project - a new, four-runway airport in the Thames Estuary favoured by London Mayor Boris Johnson.
Simon Hocquard, operations strategy and deployment director for air traffic control company Nats, said "something would have to give" if the estuary scheme went ahead while, at the same time, the existing airports carried on as normal.
Asked if all the airports, including the Boris Island scheme, could operate effectively, Mr Hocquard said: "I don't think so."
Mr Haines said the Government needed to come up with a "quite sophisticated" future aviation policy,
Any airport expansion would have to be financially viable, safe, sustainable and "not a white elephant" he said.
The Government has appointed former Financial Services Authority chairman Sir Howard Davies to head a commission to report on future aviation policy by summer 2015.
Today, Birmingham Airport chief executive Paul Kehoe told MPs that the Davies Commission had to look at the problem dispassionately and "come up with a solution that benefits the whole country and not just south east England".
Mr Kehoe said that the UK had an aviation capacity crisis but that it was "only at one airport - Heathrow".
Bristol Airport chief executive Robert Sinclair said the rise of low-cost carriers had helped aviation but now the costs facing airports and airlines were "potentially causing real challenges".