[electricron]

Interesting points about OIA subsidies, but........
Wouldn't the parking garages on OIA property be paid for by parking fees, not airline ticket fees? Ie, the subsidy being requested is for the parking garages, which can be used by the airport for both trains and planes - assuming there is a way provided to get people parking in the garage near the train platforms to the airport terminal, and vice versa, a way provided to get people parking near the airport terminal to the train platforms. A monorail line is just one way amongst many that could be used to connect the parking garages and train station and airport terminals together.
It's not unusual for almost all infrastructure located on airport property to be built, financed, and owned by the airport authority. As is, FEC is willing to build, finance, and own the railroad infrastructure.