The decision to approve a third runway at Heathrow has been welcomed by a number of airlines.
The boss of British Airways' parent company expressed relief at the announcement, and that the Government has insisted the airport should aim to " deliver a plan for expansion that keeps landing charges close to current levels".
Willie Walsh, chief executive of IAG, said: " We're pleased that a decision has finally been made but the cost of this project will make or break it. The Government's directive to cap customer charges at today's level is fundamental.
"Heathrow is the world's most expensive hub airport so it's critical that new capacity is affordable. The airport has consistently argued that the British economy will benefit if the third runway is approved.
"Heathrow want it, argued for it and now must ensure it's the UK and the travelling public who get the benefits from the runway, not the airport's owners."
The Airports Commission predicted last year that the project will cost £17.6 billion, although the airport announced in September that it could expand for less money and provide economic growth faster.
The Department for Transport's announcement noted that e xpansion costs will be paid for by the private sector, not by the taxpayer.
Mr Walsh continued: " We will be vigilant in ensuring that Heathrow does not raise charges to benefit its shareholders to the detriment of the travelling public."
Craig Kreeger, chief executive of Virgin Atlantic, said the long-haul airline will scrutinise the project to ensure that passengers are not "overburdened by paying for runways and facilities that won't be open until the mid-2020s".
He described the third runway as " an exciting, once-in-a-generation opportunity to radically transform airline competition at the UK's hub airport".
Dame Carolyn McCall, chief executive of easyJet, also welcomed the decision and confirmed that the Luton-based carrier intends to operate from an expanded Heathrow if the costs are acceptable.
She said: " This is good news for UK consumers and businesses and will help ensure that the UK is better connected to the rest of the world.
"With the right charging structure and the right infrastructure for our efficient model, easyJet plans to operate from Heathrow, in addition to our existing London bases, providing new routes and lower fares to customers."
But Dublin-based airline Ryanair claimed that additional runways at Heathrow, Gatwick and Stansted would be the best way to boost airport capacity " in a timely and cost efficient manner".
He went on: " The threat of additional runways at competitor airports will force Heathrow to keep its costs down while developing a third runway in the most timely and efficient manner.
"Today's decision, which implies that Heathrow can build a third runway at the expense of Gatwick and Stansted, will simply encourage this Spanish-owned monopoly to yet again waste billions on gold-plated expensive facilities."
Tim Alderslade, chief executive of the British Air Transport Association (BATA), the trade body representing UK airlines, said: " Our members are clear that the cost of expansion that they and their customers pay for is key and we will be scrutinising this decision and future, more detailed, plans.
"Heathrow is the most expensive hub airport in the world and airports are not funded by the taxpayer, but by passengers. Therefore any new infrastructure must be cost effective."