homunculus, I don't think you need to withdraw, as a taxpayer you have every right to expect the police to use their funds wisely.
As a number of previous posters have pointed out, the trouble is that whether air support is cost effective, (however it is delivered, helicopter, fixed wing, hover bike or 'drone') is rather subjective. One thing you can be sure of though is that police air support is subject to more financial scrutiny now, than it ever was before.
I'm sure that once all the interested parties (PCC's CC's and the Home Office to name but a few), agree on what (if anything) they would like air support to deliver, then they can work out the targets/standards/metrics against which a practical audit could be carried out. Until that is done, it's a bit like trying to determine whether the nuclear deterrent is cost effective!
Some of the points made by you and Jay (on his very successful fishing trip), are not just issues for police air support but issues for the police in general. I suspect most members of the general public have very little idea how much time the police devote to searching for vulnerable missing people.
The 'discussions' about whether searching for or pursuing, stolen cars is a sensible use of police resources is aways both interesting and entertaining. There are very few forces out there that wouldn't rather drop the whole dangerous game but for the fact that an awful lot of crime involves cars, if only as a mode of transport to and from the scene of the offence! Some considerations regarding crime and vehicles are listed below.
When a police officer becomes aware of a vehicle of interest it may be because the number plate of the car has markers on to suggest all manner of reasons that the car and driver should be stopped (being stolen is only one of them). It may be that a member of the public has reported a similar car to the police and all police officers on duty are notified to be on the lookout for such a car over the modern equivalent of the wireless radio.
Other than that, a police officer may notice a car because of the manner of driving. This generally takes three forms:-
1. The driver is obeying the street rule 'drive it like you stole it'. This often takes the form of driving in a highly dangerous manner putting other drivers, cyclists, pedestrians etc at great risk.
2. The driver is driving in a highly suspicious manner (this is frequently determined using the highly successful but now much discredited 'coppers intuition or hunch'). When members of the public driving in this way are requested to stop by the police, then, should they adopt the driving manner described in point 1 above, that is normally regarded as corroboration that the police officers 'hunch' was correct.
3. The driver and/or his (or her) passengers are recognised as being miscreants or ne'er-do-wells or known criminals or are wearing stripey pullovers and are observed carrying bags with the word 'swag' written on them. (in my part of the country an oversized flat cap would also be cause for suspicion).
It always strikes me as amusing that a number of members of the public would fully expect the police to attempt to apprehend a person who has just carried out a raid on say, a jewellers shop and run off with 30 grands worth of Ratners finest bling, yet feel that devoting the same effort to stop someone who purloins 30 grands worth of fine Bavarian engineering is wrong!
For Jay in particular, if he has such strong views (and wind up or not, his views are perfectly valid), about the sort of tasks he believes the police should prioritise, he really ought to consider putting himself up for office when the next set of Police and Crime Commissioner elections take place. Then he could determine whether his views strike a chord with the huge numbers of voters that take part in those elections (unless he lives in London of course, where he will have to try for the Mayors job)!