I'm not so sure that makes sense given ridership numbers from downtown. Even cities that have rail links to their airports make intermediate stops. I have taken the FAST [[Route 261) to DTW from downtown and although the trip via Michigan is hardly fast it does seem to serve a lot of people cheaply. Not many places can one take public transit to the airport for $2 [[or 50 cents for seniors). Some cities have door to door private shuttle service which are less than a taxi fare, but the time it takes depends on how many stops it must make to pick up other fares. That being said, I would definitely pay $5-$10 for a non-stop. Depends on the route it takes I guess.