Detroit's airport is very close to Ann Arbor. I think it is around 15-20 min drive if I remember right.
It is, but I think this one (KYIP) is even closer to Ann Arbor than DTW judging by that map.
BTW, My company (Townsend) used to have a Citation X. Almost got on it a few times, once would of been a flight to the Netherlands, with a stop in New York, and Iceland or Greenland for fuel. Its about 9-10 hours airtime, 14-16 hours total commercial. It can be done with the Citation X in about 6-8 total.
The owner of the company sold the company, kept the plane. I think he just got a brand new one, he's been leasing it and the pilots out and making a killing.