Question if he is coming to visit . . .

So, D is coming to visit However, I have a question. It's his birthday while he is here, as well as Valentines day, and unfortunately I haven't got my own place and there's not much to do around here (small city in Michigan) so I wanted to fly to Chicago with him and plan a nice little weekend there for the two of us. Is that going to be a problem flying into chicago and back into detroit metro? I wanted to know if we could go into the same lines when we get there and return. As well he's flying out of detroit metro home but he'll have his u.k. passport. What do we do???

Also, is there any recommendations on where to stay? As I haven't been to Chicago in years and can't remember where we stayed last time. We'd be there for 2 nights I'm estimating, as I'm paying for it, and well I know the touristy things to do. It doesn't have to be a really cheap hotel, but as long as its not over like 200 a night, that's a bit much.

You only go through immigration when you enter a country for the first time on a trip, not when you fly between airports within that country. So, if it's just a domestic flight between Chicago and Detroit then there's no issue here at all - you shouldn't have to go through any immigration lines or anything (just security when you check in), so it should just be a case of stepping off the plane at each end, going straight to baggage claim and then out of the airport.
 
Now, if the two airports were in different countries (i.e. you flew to Canada for the weekend), then you both would have to go through immigration each way (although I doubt this would be an issue anyway).

Awesome, I figured as much but I just wanted to double check although this is just a holiday for us in the middle of his holiday here lol. greatly appreciate your help!