The matter is still unresolved and a public inquiry is currently being held to determine whether to give Sywell Aerodrome planning permission to build a hard runway after more than seven years of wrangling.
Wellingborough Council has predicted the total cost of dealing with the plans will stand at £373,157 while Sywell Aerodrome managing director Michael Bletsoe-Brown estimated the whole saga had cost his business about £600,000.
Action group Stop The Aerodrome Runway Expansion (Stare) was formed to fight the plans and say the public inquiry has cost them £60,000.
The news has been greeted with outrage by people in the borough, who say the council's cash should have been spent more wisely.
Debbie Hollis, 41, of Racedown, Wellingborough, said: "It's a lot of money. I can't see why it has taken so long to get it sorted out. The money should have been put to better use."
Karen Worrall, 24, of Northampton Road, Wellingborough, said: "What a waste of money. Why didn't they invest the money in improving the area instead."
Sywell first applied for planning permission to build a hard runway in 1999. They were given the go-ahead in 2002 but that decision was overturned by the High Court a year later.
The aerodrome then reapplied and while the council was considering the plans, an appeal was lodged by the airfield to the Secretary of State on the basis that the authority was taking too long to come to a decision – this appeal resulted in a public inquiry being called.
The council is also processing another application from Sywell Aerodrome to build a hard runway.
A spokesman for the council said the money had paid for all the costs involved, including legal fees and hiring consultants and also included dealing with the latest application, but declined to comment further.
The public inquiry was adjourned for two weeks on Friday. Summing up is due to begin on Tuesday, August 29.