Earlier quoted context omitted.
How difficult is it to get clearance to fly a helicopter or airplane over Manhattan as they did? It seems like an unnecessary risk given the population density. For that matter wouldn't it be possible for a terrorist to get approval by creating a ruse of a legitimate (but non essential) reason?
NY ATC hates giving VFR clearance in the area. Too much jet traffic to deal with. If you can get a word in edgewise, they'll often let you out over NJ (watch out for the Teterboro jets!) but I never see anyone heading out over Manhattan. You need to be above 2000' to be legal because of the height of the buildings and then you're starting to get into the altitudes the jets are using on approach to JFK or LGA. Over th…
If LGA is landing 13 or Newark is using 11/29, then you have a conflict with the airspace over the river, but it's very rare for Newark to use 11/29, and LGA traffic counts aren't all that high to present a conflict. Plus, if you're on a clearance and being controlled by LGA tower, they'll turn you if they need to to accommodate a departure or an arrival.
I often hear pilots complain they can't get a clearance through NYC Bravo airspace, but I've only once been turned down in probably 50 attempts. That was a Thanksgiving Wednesday when they had a radar outage and they were turning everyone away who wasn't landing inside the Bravo. I've found NYC tri-Bravo controllers some of the easiest and most accommodating approach controllers to work with.