Lowe Alpine makes a duffel bag, which I think they call a travel tote, which is top-loading with a zippered flap, a handle and a shoulder strap, for carrying backpacks. I think I bought it at Campmor for under $40. I put a big (over 6000 cu. in.) backpack, with gear in the backpack, in it and checked it for recent trip by air. I also put my telescoping hiking poles in the duffel alongside the pack, disassembled and strapped together with nylon cable ties (duct tape would work) so that the top of the hand grip, not a sharp point, was at each end. Otherwise, I'm sure sooner or later a baggage handler would try to lift and toss the pack using a sternum strap or a compression strap. And there is the possibility of those straps, sliders and buckles, getting caught on conveyor belts or snagging in the luggage hold.