Kent's Manston Airport to close on 15 May
Manston Airport is to close with the loss of up to 150 jobs after a buyer was not found, its owners have said.
An airport spokesman said there had not been "a viable alternative" to allow the airport to remain open.
But Kent MP Sir Roger Gale said the airport should have negotiated over the offers.
Campaigners have vowed to continue fighting to keep Manston open.
In a statement, the airport spokesman said it had also considered business proposals put forward by staff but those would have still required losses to be subsidised.
"In the absence of other options, the decision has been taken to close the airport on 15 May," it said.
"Individual consultation will now take place with all staff members who will be supported through this process."
Staff were told of the decision to close the airport at a meeting on Tuesday morning.
The site was bought by Ann Gloag, who co-founded the Stagecoach Group, for £1 last year.
In March, the airport said it was in talks about closing because it was losing £10,000 a day.
Several airlines have pulled out, including KLM, which ran two daily flights to Amsterdam.
In a joint statement, local Conservative MPs Sir Roger Gale and Laura Sandys, said there was "ongoing and serious interest" in the acquisition of Manston as a working airport and they hoped the current owners could be persuaded to reconsider.
"We are convinced that, given more time, real progress could have been made and it is thus hugely disappointing that the decision has been taken to close it."
US firm RiverOak Investment, which is based in Stamford, Connecticut, said it had made an offer to acquire 100% of the shares in the company that owned Manston Airport.
'Not the end'
It said it had $350m (£206m) in assets and a successful track record of turning around "troubled operating and real estate assets".
The company said it had developed a long-term plan to own and manage Manston as an airport.
In a statement, it said: "RiverOak is distressed to learn of the announced closure of Manston today and remains willing to engage with all parties to achieve a solution which allows the airport to continue operating and preserves the jobs of its staff."
Wendy Fraser, group secretary of Save Manston Airport, said campaigners would be stepping up their campaign to keep the airport open
"We'll fight to reopen it if it does close, and we will not let this be made into anything but an airport," she said.
Founder of the campaign group Dan Light added: "I believe that something can be done. I mean, it's not the end yet. It may look like it is, but we're going to fight to the bitter end."