British Airways has welcomed the UK Government's decision to allow a new runway at Heathrow if environmental goals are met.
The UK government has announced a 30-year airports programme
BA's chief executive Rod Eddington called it "excellent news" for the air industry, businesses and tourism.
Other airlines and unions cheered the news, but demanded swift action to ensure the UK keeps up with its rivals.
Airline BMI warned that the decision to build a new runway at Stansted first could harm Heathrow's status.
Ahead of the announcement, British Airways had warned that aviation could face the sort of decline the shipbuilding and coal mining industries suffered if no extra Heathrow runway was contemplated.
Most experts had expected Transport Secretary Alistair Darling to announce a new runway for Stansted, but to block expansion at Heathrow.
Analysts had said that a decision to allow a new runway at Stansted, but not Heathrow, would be a huge blow for BA and a boost for budget airlines such as Easyjet and Ryanair.
Aviation industry facts and figures
Employs half a million people in UK
Adds £10bn to UK GDP
180 million passengers use UK airports every year
For every one million passengers, 1,000 airport jobs and 2,000 supply chain workers are sustained
One fifth of UK exports are by air
However, he said Stansted would get a second runway by 2011, with Heathrow to get a third by 2020 if it meets environmental targets such as a car charging scheme.
Mr Darling said the expansion of Heathrow was important for the UK to be able to continue to compete with international hubs in Paris and Amsterdam.
BA's Rod Eddington said the government's decision was an "effective, forward-looking" policy.
He vowed to work with the government and local authorities to address environmental issues surrounding the venture.
The British Chamber of Commerce (BCC) also welcomed the decision saying its members were "very pleased that the government has finally chosen to grasp the nettle on aviation policy".
BCC director general David Frost underlined the fact that action now was "crucial" before UK firms lost out to their international rivals.
Too late for Heathrow?
But rival airline BMI said it was "disappointed" that Stansted would get a new runway before Heathrow.
BMI chairman Sir Michael Bishop said the decision "could seriously damage its pre-eminent position as one of the world's leading airports".
He also sounded a note of caution over the funding of a new runway at Stansted saying it posed serious questions about how airport operator BAA would finance the development.
He added that BMI did not believe the investment could be funded without cross-subsidy from Heathrow - which would mean higher charges being levied on airlines using the airport.
"I can promise that we will fight such a threat every step of the way," Sir Michael said, adding that BMI would demand the break up of BAA so that it did not hold a "monopoly over capacity" in the south east of England.
The Transport and General Workers Union (T&G) also expressed concern at the Heathrow delay.
"To avoid a short-term fix and promote a long-term future for UK aviation, we must see development at Heathrow sooner rather than later," T&G general secretary Tony Woodley warned.
But the union said overall the White Paper would "secure much needed jobs in aviation and the wider economy".