Tom Fleischman wrote:

The corridor [...]
includes helicopter and sometimes seaplane traffic.

Sometimes? I used to have an office overlooking the East River a few
blocks from the 23rd street SPB. Seaplanes come in and out on a regular
basis all day long. Scheduled service out to the Hamptons. Mostly Cessna
Caravan amphibians. I chatted with one of the pilots one day. He said the
float system cost as much as the rest of the airplane.