The Llanbedr airfield in Gwynedd remains in the running to be the home of Europe's first commercial spaceport.
The site was among eight across the UK highlighted by the UK Government in July.
The Government wants to have a spaceport to launch flights from commercial spaceplanes to be up and running by 2018.
A consultation on the project has now come to an end.
The UK Government has ruled out two airfields at RAF Lossiemouth and Kinloss Barracks, citing their role in defence operations.
All but one of the other possible sites - Campbeltown, Glasgow Prestwick and Stornoway - are in Scotland.
Newquay in Cornwall is the only English site under consideration.
The sites are being looked at for the following reasons:
They are existing civilian or military sites with a runway which is, or is capable of being extended to, over 3000m in length
They are away from densely populated areas
The airspace around them could be properly segregated to ensure safety
Later this year the Government will publish a detailed list of technical requirements for the spaceport project, before inviting further proposals from the shortlisted sites.