I happen to think LaFleur makes the best "Michigan" sauce (which is basically a meat sauce with a high meat to sauce ratio). Slapping that on a steamed hotdog for "un vrai hotdog michigan" is the best thing. I also happen to like their poutine sauce, which seems like it's the same recipe they've been using forever, but it's a bit salty. Their fries are great on their own, though I especially like them with salt and vinegar. The classic "steamie" hotdogs are good too, they have a drier coleslaw mix than some other places. These items literally haven't changed at all to my recollection, which is really part of the charm. This is simple, inexpensive, nostalgic fare.
Even though it's a tiny joint where you may have to wait in line for a while (usually there are only 2 people working at a time) it's worth it - no trip to the airport is complete without a meal from LaFleur afterward!