At both JFK and EWR (Newark) the air trains are also the links out to NY/NJ mass transit (LIRR/Subway from JFK and NJT from EWR). I always thought/it's been my

At both JFK and EWR (Newark) the air trains are also the links out to NY/NJ mass transit (LIRR/Subway from JFK and NJT from EWR). I always thought/it's been my experience they were free for intra-terminal stops and you only had to pay if you were at an end that allowed outside access. It's basically their way of increasing the price of what would otherwise be a rather cheap trip on public transit (NY Penn Station to Newark Penn Station is about $5, but to the airport is $15 even though the added distance is negligible)