Plans for a new £2bn airport in the Severn Estuary have been rejected by the UK Government.
The terminal at Cardiff International Airport is set to expand
The proposal for the Severnside airport plan was submitted earlier this year, and could have been ready to serve Wales and the west of England by 2012.
The decision to drop the scheme emerged in the government's 30-year plan for UK air travel unveiled in the aviation white paper on Thursday.
It said Cardiff International Airport needs a bigger terminal and easier access, and suggested the Welsh assembly should set up "a route development fund" to boost Welsh air links.
Similar schemes exist in Scotland and Northern Ireland, and could lure transcontinental airlines to south Wales.
The white paper also revealed expansion at Bristol, Manchester and Birmingham airports but, speaking to BBC Wales, Transport Minister Kim Howells strongly denied claims that Cardiff had been downgraded.
"This is a nonsense - Cardiff is set to grow from 1.5m passengers to 5m a year," said Mr Howells.
There will be no new airport in the Severn Estuary
He said when access links were improved, Cardiff would be a much more attractive proposition for airlines, but the Severnside plan had not "stacked up commercially".
"We did not see a future or even a start-up for the proposals we were presented with on Severnside," he said.
The Severnside airport would have been built near Newport, south Wales, with runways on a man-made island in the Severn Estuary.
Supporters had said the airport could have handled 30m passengers a year by 2030 and helped create 13,000 jobs.
Last year, Transport Minister Alistair Darling said the proposal would only have been likely to go ahead if airports at Cardiff or Bristol closed.
Centre of excellence
Michael Stephen, head of the Severnside proposal, said the Department for Transport had held "a blinkered attitude to solving the problem of future air transport demand in the south east of England".
He said the white paper "failed to take a strategic view" and allowed London business interests to "prevail over the legitimate concerns of people in south east England and South Wales".
Welsh Assembly Economic Development Minister Andrew Davies said he would "look closely" at introducing a special fund to support services from Cardiff.
He also said he would be consulting on proposals for intra-Wales air services early next year as he was especially "keen to develop better transport links with north Wales".
Mr Davies also agreed that south Wales had the potential to develop a centre of excellence for aircraft maintenance and training.
Proposals for Severnside had been fully examined, but he said establishing a new airport was "very risky".