As far as airports go, I have had no problems with either willow run or Detroit city. But, you still have to get from the airport to the museum, and I would feel much more comfortable taking a wrong turn from willow run than Detroit city. It was amazing to see the blocks of empty businesses and houses just outside city airport. In some cases whole boarded up apartment buildings.
Be warned, one day is not enough for the museum and the village. Sometimes you can also get tours of the ford plant.