If you're putting your instrument cases on the airplane through the luggage check, wrap around the whole case and cover all the latches with at least 2 layers of tape. This will make them less likely to pop open and get torn off in handling.

As soon as you touch down and reclaim your instrument, unwind it and throw it away (the tape, I mean) -- less likely to leave marks on the case the shorter a time it's on there.

Alex