You might want to check the Islanders home schedule. Visiting teams fly in and out of Republic during their season (as do the Islanders themselves). The aircraft you saw depart was probably a 737 charter. In addition, there are two "horse trailers" serving the interests of the horsey set at Belmont and now at Aquaduct during their seasons. (These are converted Boeing 727's which have aged far beyond their usefulness to the airlines, but are perfectly comfortable for the thoroughbred horse to ride.)
