(And I Don't think the airport would wan't to build a monorail all the way over to LaGuardia lol )
The JFK airtrain isn't a monorail.... it's a standard gauge heavy rail system which IIRC uses a Linear Induction system for propulsion.
But regardless, look at the Tokyo Haneida airport Monorail. It goes from the center of Tokyo all the way to the airport.
I think there is a Tokyo Haneida Airport Monorail route for BVE out there actually...
I think that the MTA should have built a ramp up from the center tracks on the Rockaway line at Howard Beach to
connect with a circular line which goes to all the terminals instead of the airtrain. This would provide
one-seat access to the JFK terminals from the rest of the city.