More than 150 jobs are in the balance at Manston Airport in Kent, for which Stagecoach co-founder Ann Gloag paid £1 last year.
Local Conservative MP Roger Gale said an unnamed American firm had come forward yesterday with a formal bid to buy it as a going concern. He described the bid as "viable" and "realistic", and said he believed negotiations between the firm and Ms Gloag would centre on the price.
Efforts have been under way since March to find a buyer for the airport to save up to 150 mainly part-time jobs at Manston, which has suffered losses of £10,000 a day.
But in a statement Manston Airport said the proposal had been rejected for "a number of reasons".
"The basis of this proposal had already been put to the shareholders verbally on Friday and had been rejected."