Originally Posted by Yoshi212

When you get to the Subway entry point after riding the air train there are two exit options. One is exit to the "street" (into the station) where you pay to leave and the other is into the subway system. You can easily exit to the "street" where you'd have access once again to Metrocard machines to add time/funds using the same $1 Metrocard & then enter the subway section. It's an extra step but not that time consuming or all that complicated.