Interesting. Haven't flown with a big frame pack since before 9/11. Did so to Alaska and back with a Kelty frame pack for a little backpacking/mountaineering trip. Checked the pack as luggage. Made sure all the straps were removed and tucked inside so they wouldn't get caught on the conveyor belts. It worked fine, but we were all worried about our packs on the way up.
Coming home, not so much. We were too tired to be worried about the packs! Every pack held up fine.
Made a couple of cross-country flights with a military frame pack too. Just checked it.
