We saw what happened with Amtrack - IMO it would be cheaper to do this with airlines. Mass transit in municipalities is not private to my knowledge.
Can't really argue that airlines are "free enterprise" when it's the most regulated industry in history. The "utility" argument is valid.
Nevertheless - I'm speculating that 1 trunk carrier like DAL will be funded and redundant svc be eliminated and certainly SWA. The LCC's will remain but 3 large carriers is too much to be expected.