I would assume that air traffic control is similar to ground control for the purposes of this analogy. Does that 35% number take into account the costs of air traffic control? I'm assuming that the airport (and not the airlines) covers those costs.
As far as I know air traffic control is part of FAA and it's covered by taxpayers (or perhaps, it's an extra charge in the ticket?). In any case, ground control will probably be a lot less expensive since it's just one team in one location, while air traffic control covers the entire country.
