Ann Arbor is located about 30 minutes from Detroit Metropolitan Wayne County Airport (DTW). This is one of Delta’s hub airports, which means they provide the majority of the flights, but all the major airlines provide service.
Ride-share options such as Lyft and Uber as available. There is also a bus service operated by the The Ride that will take you directly from the airport to the Blake Transit Center in downtown Ann Arbor.
The Ann Arbor Convention Visitor’s Bureau also maintains a listing of airport shuttle options.