The concept of dedicated cars for airport service is not new: Eight SEPTA Silverliner IIIs were overhauled for PHL service with luggage racks, the last 40 CTA 2600s (3161-3200) delivered in early 1987 had them, as would be Cleveland's Airporter MUs of 1967-1970 and the UP Express DMUs and the 1200 series "A" unit R46s for the JFK Express. It is rumored both London's 1973 Piccadilly stock and NYCT's R44s were both designed for airport service to LHR and JFK respectively.
But with NYCT's large fleet, a dedicated, captive fleet would be difficult to manage, especially on the N Line which shares a pooled fleet with the Q and W at Coney Island. A dedicated fleet would be much easier on an isolated line such as the 7.
The Astoria transfer station with Amtrak is something I've imagined for over 20 years. If the infrastructure is already there... I could see select Regionals only here, no Acela Express service.
Since my friend continues to chain smoke nonstop, she is probably an Alco.