After attending the event—on the next day or two later—you can catch sight of the B-17 and B-24 bombers overhead, as they take passenger-flights over the Lakes Region. The B-24 is especially remarkable, as nearly 20,000 were built for the war effort, and only
two (2) exist today!
Both have those "round" radial engines. It's not a particularly noisy engine, making a "chuff-chuff-chuff-chuff-chuff-chuff" sound.

Listen for that deep and distinctive radial engine sound overhead
after the main event.