Highlands and Islands Airport Limited said it did not have the resources to take on the project itself.
But Hial's chairman Grenville Johnson added that the company would probably offer what help it could to an organisation that could fund it.
Stornoway and Campbeltown are on a list of possible spaceport locations.
Mr Johnson said: "If someone comes along and says that they would like to look at Stornoway and discuss it with us then of course we will do that."
He said any discussions would have to have the blessing of the Scottish government which owns Hial.
Mr Johnson added: "What we are saying is that we simply don't have the resources to do this, but we are there to help."
The UK government issued a shortlist of aerodromes that could host a UK spaceport on Tuesday.
The list reduced the number of runways first suggested as candidates when last year's consultation got under way.
Still in are Campbeltown, Glasgow Prestwick, and Stornoway in Scotland; Newquay in England and Llanbedr in Wales. RAF Leuchars was confirmed as a potential temporary facility.
RAF Lossiemouth and Kinloss Barracks in Scotland were ruled out. The decision was made for operational defence reasons, the government said.
Ministers are keen to see the spaceport established by 2018.
The emphasis will be on the expected emergence of a new breed of low-cost rocket planes that can launch fare-paying passengers to sub-orbital altitudes and also satellites into orbit.
Most of potential vehicles are still quite some time away from flying.
But ministers believe that if the UK gets its act together now, the nation can catch the first wave when it arrives.
Precisely where the British spaceport would be sited will depend on a number of factors, but the overriding imperative of the licensing authorities will be to find a location that limits danger and inconvenience to the general public.
The operator of airports at Stornoway and Campbeltown has said it is open to the idea of either site being developed as a UK spaceport.