You will find all major and most minor airlines at Detroit Metro Airport. It is located approximately 20 minutes from the university. You do not need a reservation, but can find their ticket counters located in the baggage claim area. Their shuttles run every hour on the hour from 7am - 12 midnight. You may also take a cab or rent a car, however the cost will be more.
Some hotels offer shuttles from the airport as well.
Also, approximately 20 minutes from the university, it is accessible via taxi.