Plans for a second runway and terminal at Stansted Airport in Essex have been unveiled by airport operator BAA.
BAA illustration of revised plan for new terminal at Stansted
The development would take up less land than originally planned and have opening costs of £1.4bn - £300m less than was initially estimated, said BAA.
Uttlesford District Council last year blocked plans to extend the existing runway at Stansted.
Members of the Stop Stansted Expansion (SSE) campaign group are to continue their protest against the plans.
BAA said the overall cost of the project would run up to £2.2bn down from the £2.7bn forecast in 2005.
Subject to planning permission, the runway could be operating by 2015 and accommodate an extra 10m passengers a year.
It is expected that one runway will be used for landings, and one for take-offs.
Stephen Nelson, chief executive officer of BAA, said: "This will provide the increased runway capacity that the UK economy needs, good facilities for passengers and value for money for airlines.
"We have also worked hard to reduce the impact on the local environment."
Stop Stansted Expansion said a second runway would be an "environmental catastrophe".
The group said it was also concerned about the regional and local impacts if Stansted was allowed to grow.
In November, Uttlesford Council turned down expansion plans for Stansted which would have increased passenger numbers, amid objections including the effect on climate change.
Environmental campaigners hailed the council's decision as a benchmark, saying it was the first time climate change had been listed as a reason for refusing a planning application.
Terry Morgan, Stansted's managing director, said the airport would appeal and seek to have the issue decided by a government inspector at a planning inquiry.