Last year, the police granted businesses operating aircraft from the former HMS Daedalus site a five-month stay of execution after initially moving to shut the site down immediately. The period of grace ends on Wednesday.
Hampshire Constabulary, which runs the Maritime Coastguard Agency-owned site, announced in October that it intended to stop all general aviation because it would not use taxpayers' money to cover the £300,000 to bring the airfield up to safety standards.
It has already granted two stays of execution, but the Lee Flying Association is confident it has addressed all the force's issues.
The association's Steve Cockshott, pictured, said: 'We are giving it 70/30 at the moment – all the issues that were raised by the police have been addressed.
'We have put an awful lot of work into this, so unless they come back with something completely new we should be all right.'
The group may not be able to introduce all of the new measures by the May 14 deadline.
Mr Cockshott added: 'We have done everything we can, but until the police make their decision, there are some things that they will need to do.
'We hope they will see it has been running completely safely since they made the announcement, and there will be no reason why we can't keep running, but will introduce the new measures as soon as possible.'
Police spokesman Ben White said: 'There are still a couple of options being considered. The LFA's proposal is central to the discussion and it is still being looked at.
'The chief constable is on leave until Monday, and it is something he said he wanted to make the decision on himself.'