Couple more things I wanted to mention, and I apologize for the somewhat disjointed writing. It's tough to organize this clearly.
Regarding my earlier post about the blurb on the PA website about photography, I realize that it is likely posted with respect to commercial photography and the media, but my point was that it is the only place I've seen the PA publish anything about photography and video anywhere, and I'm sure they'll try to leverage it somehow given the chance.
But let me play devil's advocate here for a minute.
The issue with being on public property for any reason other than having official business has come up before in several court cases, including one going back to 1992 involving the PA. The issue is that even though a government-owned (city, state, federal) or operated airport is public property, there may be limitations depending to what extent the property has been deemed a public forum. In other words, not all public property is freely accessible at all times.
For example, public schools are public property, but generally forbid anyone from being there unless they are a student, parent, guardian, faculty, or otherwise authorized to be there. Courthouses are public buildings, but have restrictions on photography in certain areas. Military installations are on public land, but generally forbid photography at all times.
I made mention in my earlier post of the distinction between land-side airport property (i.e. streets, parking lots, sidewalks, etc.) and the actual terminals. As soon as you step foot inside a terminal, your rights change. Your rights are definitely strongest while you are land-side (parking lot, street, sidewalk, etc) because those areas are generally unrestricted to the public. But while you may have a strong defense if you get hassled in the parking lot, terminals are more restrictive in the sense of no longer being a completely open public forum. Although the terminal buildings at PA airports are technically owned by the PA and considered public buildings, they are operated by individual airlines and/or private companies, so your rights inside them are no longer as free as being completely public. In that case, you can be asked to leave if you aren't there for a legitimate travel or business reason. I don't want to mention the TSA here, because when TSA incidents are mentioned, generally they involve passengers who are in the terminal presumably to travel anyway.
There's another issue at play here, in that while the property might be managed by the PA, once you step or point your camera air-side (and someone correct me on this if I'm wrong) but you are then also under the jurisdiction of the FAA. The FAA has clearly stated that it has no rules banning photography.
So to confuse legal matters more, you are standing on public city property managed by a local government agency while you are taking photographs of aircraft under jurisdiction of the FAA. So while you are free to photograph aircraft to your heart's content from land-side, the PA still discourages it, yet you are standing on land that is generally considered a public forum.
My guess is that if the PA ever goes on record to ban non-traveling or non-essential public (i.e. persons who have no business being at an airport other than travel, employment or legitimate business) on its property entirely (photography or not) or tries to enforce all airport property as having limited public access, it may face First Amendment civil action. That may be why there is no "official" stance, even though it might be strongly discouraged.
Hate to say it, but I think one of the best ways to clear up the issue of photographing (or just watching planes) on airport property is to get an attorney to contact the PA's legal department and get something official. Unfortunately, failing that, the only other way this will happen, as someone mentioned earlier, is when a civil suit is brought on the PA and/or NYC.
References:
http://www.citmedialaw.org/legal-gui...ublic-property
http://www.law.cornell.edu/supct/html/91-155.ZS.html
http://www.airliners.net/aviation-fo...ad.main/40870/

