Back in 1978, I received my private pilots license,and at the same time we purchased a 1977 Piper Archer and based it at Teterboro airport, New Jersey. One of my very favorite things to do was to simply go for a short flight down the Hudson and back, and I repeated this flight many, many times over the ensuing nine years frequently taking CBS'ers along for the ride.
It never occured to me to return via the East River and a very low percentage turn, to overfly Manhattan, and then up the Hudson to the GW bridge, and then on into Teterboro. The East River route was somewhat hazardous due to the heavy helicopter and intermixed general aviation traffic.
It is possible that the flight instructor and Mr. Lidle were taken by suprise that they would be entering La Guardia's restricted airspace if they proceeded any further up river! This could have necessitated a maneuver that could have been a 180 or a 90 across Manhattan.
It should be noted that the instructor was from California and most all of Llidle's hours were also built on the West Coast. I feel confident that the NTSB and the FAA will be looking into the wisdom of an instructor from the West Coast, and a low-time pilot, flying in such a busy airspace.
I can only hope that he was not receiving instrument instruction when this accident took place, as this type of instruction is very demanding. Almost all of my instrument and private training took place originating at Teterboro, but my river flying was always VFR. It saddens me to realize that two lives were lost needlesly. Since the accident, the FAA has modified the rules for flying in that environment... constant communication must be maintained.
I don't have airline Captain hours, but just enough to feel qualified to participate in conjecture. May they rest in peace.