Even assuming that those rules were changed to allow this (I don't think they were as a professional in this industry, but it's too early in the morning to go look it up) and that the current form somehow survives in the Trump regime, I don't think a regional system of any kind can substitute for an airport people mover. If you go to airports that have these systems, the headway is like 60 seconds. The vehicles are tiny and the trains are short. They're just different from more regional (or even local) transit because they're optimized for their purpose.
I can think of a couple of examples of airport people moving being done by real transit - Minneapolis and Saint Louis might be the only ones in the US, while Heathrow and maybe a couple others could be found internationally. In all of these cases, though, the transit is intended to provide multipoint access from the city to the airport, not to circulate people on the airport itself (though you can use it that way). Far more common is a single point of transfer between the APM and the transit system, like you see at (among many others) JFK, Newark, Miami, O'Hare, Atlanta, DFW, Phoenix, SFO, and soon at LAX. To use SFO as an example: BART trains to the City from SFO run at minimum every 20 minutes (by line) but the APM upstairs is running more than every 2 minutes.