Spot on guys! I've kept quiet on this for a number of reasons but feel it is time to step in with a couple of quick comments. Most people have the right idea about how to react to being questioned i.e. act civilly and don't be a smart arse but there are always a few who will spout off about this, that and the other. The officers you are dealing with will undoubtedly have heard every lame excuse, lie and piece of bull***** imagineable everyday of their working lives, so you bear that in mind when responding to them.
What people seem to forget is that the police officers have a multitude of laws to learn and more importantly
how to apply them. Any fool can quote the Theft Act but do you know the ins and outs of all the differing sections (theft, deception, burglary, robbery, etc etc) and all the related laws? Then look at Offences Against the Persons Act which deals with the various form of assault. Multiply that by God knows how many statutes, regulations and Codes of Practice and you might get an idea as to why the laws on photography are probably way down the list of required reading for police officers never mind a hobby bobby like the PCSO.
As to the original OP saying 'Of course, I'm planning to blow up the runway' what sort of treatment would you expect to receive after that? I see from your later posts that you realise it probably wasn't the best thing to say but you were asking for trouble.
As to complaining about treatment received after waving around a "toy gun" I think the poster got off lightly. For a grown adult to behave like that in public is stupid beyond belief. What if a passing member of the public had called the police to say there was a man armed with a gun (the call would have been made in good faith)? Had they turned up to see someone pointing a gun at passing traffic that "prank" could have ended up with tragic consequences for everyone involved. And for those that harp on about toy guns let me show you a few examples....(just put in toy gun to Google Images and see what you get)
Put yourself in the officers position, you receive a call saying that there is a man armed with a gun. You are going into an unknown situation with the real possibility that you will be facing an armed suspect. The andrenaline is pumping and you turn up to see someone with one of the above, what would you do? Ask him if wants a cup of tea? No, of course not. You are going to deal with the situation aggressively to try and ensure no-one gets shot. If the 'suspect' get shouted at and called a pratt or a few other names then boo-*******-hoo. Maybe you will think before acting next time.
If you are going to photograph what could be construed as sensitive areas such as airport make a quick call to the local cop-shop to let them know what you are doing - it could save you some hassle.
[/rant off]