BZ,
I'm house at Cook and have used every airport within reasonable distance. Detroit Wayne is 2 + hours away in heavy traffic. Closest is South Bend (SBN). Service by all major carriers, very small, very timely, limited flights ~ 45 miles. Six turns from the airport to the plant. Kalamazoo (AZO) also has limited flights but a straight shot on I-94 ~ 65 miles . Grand Rapids (GFIA) is a very new and nice airport, lots of flights but might be too far to be practical ~ 85 miles. Midway (MDW) is a little farther but the Chicago traffic has very heavy construction, no doubt a result of the Recovery Dollars. If you come this way there is a relatively new Hampton Inn about four miles from the plant. PM if you need anything.