Unite the union has hit out at the bosses of Manston Airport for failing to enter into "meaningful" talks to save airport.
They say workers at the airport, which is due to close on Thursday, are looking to take out grievances against the management for not fully exploring a £5 million offer made by American firm RiverOak Investment Corporation.
It is believed the Connecticut-based company might make an improved offer for the Kent airport before the closure deadline.
Unite, which represents about half of the 140- strong workforce, said at a final meeting today the airport bosses were "unable to give a coherent reason" why the first offer had been rejected.
"We will be taking legal advice to support our members in taking out grievances against the company for its abject failure to enter into meaningful talks with Unite to save the airport and the jobs of the workforce," said Unite regional officer Ian McCoulough.
"The closure of the airport could also adversely affect up to 500 more jobs in the wider supply chain.
"We believe Manston should continue as a viable airport. It is vital to the local economy in terms of employment and economic growth in the county."
The airport was bought last October by Ann Gloag, who co-founded the Stagecoach Group, for £1.
The origins of the airport stretch back to the First World War and during the Second World War, Manston was heavily bombed during the Battle of Britain.
A campaign group, Save Manston, carried out a PR stunt today, driving two cars from the House of Commons to Gatwick and Manston respectively and timing the two journeys.
