No, it's entirely the engines — there are a lot of moving pieces of metal that have to safely expand and contract in understood cycles. The brakes and wheels are fine with tight turns (assuming you don't have to use max braking). Southwest operates on a very similar timetable, and in fact flies a few of the more-trafficked Hawaii island hops. The difference is that Hawaiian's 717s _only_ fly island hops all day, every day. Southwest rotates its planes, so any given plane will do at max two island hops before it flies the 6 hours back to mainland and gets plenty of cooling time, e.g., LAX -> Honolulu -> Hilo -> Honolulu -> LAX.