I don't want to advertise an instrument or another, and considering tcas way too expensive and useful mainly for the big birds, I have an idea on how to constantly be aware of traffic in the vicinity without the use of ATC, which is not needed if you fly outside controlled airspace or even worse by making the corridor a controlled airspace which would mean the end of plane and heli rides around manhattan. Gliders in europe have started fitting a small instrument (as cockpits are small and cramped up to every usable inch) called Flarm or another one called T-Advisor DSX. Apart the fact that later model didn't see each other any more for some strange commercial reason, fitting these instruments on gliders reduced significantly the possibility of an air mishaps alongside ridges or thermalling up together with many others in the same thermal. Both instruments work with GPS and a small transmitter that locate other similar instruments in the vicinity that is then displayed as a small led lighting up around your plane in the direction of the interested traffic. I did flew the corridor once with an instructor from nassau flyers and enjoyed it very much. visibility was probably less the 3 miles after abeam central park, but we were still able to spot a banner towed by a PA18, slower than our 172, we just duck a couple hundred feet and overtook him. As an italian ATCo I'm against the idea to rely such huge amount of heterogeneous traffic to atc, as it would surely impact on the availability and economy of said route, especially as it would have little radar coverage and a very narrow space to keep them separeted, but that is just my opinion.