You'll probably be on a small regional jet to Detroit, might not even have first class or any real closet space. If your meeting is same day wear the suit and lay the jacket in an overhead. If it isn't same day just carry on in a garment bag, put in overhead with your briefcase under the seat in front of you, and iron at the hotel. No matter what you do it's gonna get at least a little wrinkly. Or you could always try this on the plane, but you may get tackled by an air marshall...
The small regional jet is your biggest issue. Little planes often don't have space to hang up things . . . and if they do, the space is taken by the business class and frequent fliers who board first.
You may want to pack your pants, but wear your jacket, then just hold it in your lap or put it on top of something in the carry on compartment.
Usually, you can have one carry on and one "personal item," such as a briefcase. I usually travel with my suitcase and briefcase. Only on the little jets do I have to gate check the suitcase. If you have a garment bag with only a suit, you should be able to take it on the plane with you, unless it is a big luggage-type garment bag.
Also, many hotels have laundry service that will do "pressing" for you.
