Do they really though? I don't know any numbers, but i would imagine that the airports at least make up some if not all of the cost of equivalent railroads? I get that the airport can service a lot more destinations than a trainstation( overseas etc ), but i'm not totally convinced that rail infrastructure is that much more expensive than for air.
The cost of airport security etc should probably also be thought of as infrastructure costs.
The new high-speed connection between Berlin and Munich cost about eight million Euros per kilometer. That was a bit on the high side because acquiring the land was expensive. Switzerland spends about two billion Franks a year on maintenance of its tracks.
