The Institute of Welsh Affairs report is proposing a new Severnside Airport:
- Could be built on the edge of the estuary between Newport and Chepstow
- Would take nearly 10 years to plan and build
- Would have 10-11 million passengers a year from the start
- Would have convenient access to the motorway system and the new electrified rail service
- Would have minimal noise pollution, with planes able to take-off and land over water
- Would become the UK's first purpose-built 24-hour cargo airport
Bristol Airport reacted to the proposal it should be closed and replaced with a larger airport inside Wales by insisting it is "well positioned to meet the connectivity requirements of both regions in the medium and long term."
"No doubt the Airports Commission will receive many proposals for airport schemes right across the UK. It is important that these are deliverable solutions not somewhat far-fetched proposals reliant on the forced closure of a successful, privately owned airport which supports thousands of jobs."
The Severnside Airport proposal has been submitted to the UK Government's Airports Commission, which is looking into airport capacity around the UK. The commission says it is not responding to individual bits of evidence currently.
John Osmond, Director of the Institute of Welsh Affairs, told us "Cardiff Airport is in the wrong place in relation to the population of the region."
The think tank has acknowledged that Bristol Airport is more successful, but argues that neither existing airport is in an ideal location, or has good enough regional transport links.
Cardiff Airport and Bristol Airport should both close, and be replaced by a new larger 'Severnside Airport' serving south west Britain, according to an influential think tank.
Research published today by the Institute of Welsh Affairs recommends the new airport should be built on the edge of the estuary between Newport and Chepstow, with convenient access to the motorway system and a newly-electrified rail service the key benefits.
The study, carried out by aviation consultants MSP Solutions, supports the Welsh Government's plan to buy Cardiff Airport, but only in the short term.
It warns there could be "a serious worsening of air connectivity" for Wales, unless something is done.
In 2003, the UK Government rejected a previous proposal for an airport to be built alongside the Severn estuary.