Hampshire, Surrey and Sussex police forces will share two helicopters
Hampshire police's move to share two helicopters with Surrey and Sussex forces, rather than use its own plane has caused concern among officers.
The force is one of two in England only using a fixed-wing spotter plane.
Flying two helicopters, based at RAF Odiham in Hampshire and Shoreham airport in West Sussex, could save up to £8m in five years for the forces.
However the Police Federation has identified areas where levels of police air cover could be affected.
Chairman of the Hampshire branch of the Police Federation John Apter said although he was "convinced" by the financial reasons for the decision, members on the Isle of Wight and in the New Forest had expressed fears of not having the same level of air cover they depend on.
Mr Apter said: "I'm confident the service won't be badly affected, but we have to accept that in reducing from three to two aircraft, there has got to be a level of service that is diminished.
"The service I hope we will obtain will be adequate but it's clearly not the 'Rolls Royce' service we've been used to."
Hampshire Police Authority chairperson Jacqui Rayment defended the decision.
She said evolving technology means helicopters are able to achieve more.
"This is a new way of doing business. We've got to recognise the fact policing needs have changed. We are confident and assured there won't be a reduced service, if anything it will be an enhanced service."
Direct comparisons of response times between planes and helicopters are complex.
Helicopters arrive at closer incidents quicker, can fly lower and hover and offer the crew better visibility. Fixed-wing planes can stay airborne for longer and operate over water.
Hampshire's air support unit provides airborne surveillance as well as helping police on the ground deal with major incidents.
In 1985 two police officers were killed when their aircraft crashed in woods near Ringwood shortly after the unit was set up.
Airborne surveillance provides vital support to officers on the ground
Mr Apter said the issue of shared helicopters was "an emotional debate" as well as a business decision.
He continued: "We don't want to forget the commitment, passion and dedication the staff and officers have strived for and provided over all these years."
Jacqui Rayment said: "Looking at the business case, it makes sense we move to this. Of course we are mindful staff and pilots will have to work in a different way."
Ms Rayment insisted the authority had taken a "hard look" at the decision and "many of the concerns will have gone away in a year from now."
For Mr Apter, the move is symptomatic of the current climate. He said: "Policing is going to change in future and this is a sign of things to come."