Hi Thomas I certanly understand how you feel, like you I am a multiple transport photogrpaher, mostley ships and trains by occasionaly planes. For Shipspotting in here in Hobart, Tasmania, Australia we still have some wharfs that we can get on with out too many hassles as these wharfs are very very infrquently used (apart from the summer, the port in general is infrequently used buts thats another story) these wharfs we can get on offer us vantage points of one of the deep water berths in Hobart that is used for the large cruise ships and Antarctic Support Vessels. The port of Hobart is luck to have many public open spaces all around it that offer good vantage points for photos. Yeah we do have the odd run in with the security guards (Rent a cops) who think they are all very important. But most of them mind their business, I just flash my work ID (I work for the social security office) and they normaly leave me alone as they are all casula employees and the panic i will dob them in for not reporting their earnings!
As for Hobart Airport, I haven't done any plane spotting for a long time as I only photo planes when I know their is something special coming 737's and A320's get a bit borng after a while, I have only had one run in at Hobart Airport and that was on the Tarmack when I was trying to take a photo of my sone going out to the plane as it was his first time on a plane.
But even the trains are getting hard to photo in Tassie now as they are having a security person following the trains by road and they pounce as soon as you step on to railway property and as soon as you get a camera out threaten to call the police, but us train spotters just ingnore them as most of the line in Southern Tasmania is out of Mobile Phone Range anyway.
But I guess Thomas we just have to live with these security conditions, the day will come where the Transport operators, will just turn round and say to Government to shove the securty as they can't afford to put the prices up to cover ohter wise they will start loosing business and I understand there are already some smaller ports in the US and Europe that have scaled back the ISPS stuff.