UL duffel

I have one that is 8.2oz. Send me a PM if you are interested :)

Outdoor Products makes a lot of different sizes of duffel bags. Also, there are thin ones and thicker ones. That's what I used for the last time I needed to pack a backpack for the airline.

–B.G.–

Usually airlines can wrap your pack in stretch plastic material at the check in to protect it and other baggage. I've purchased cheap duffel's at the local thrift store before. Less than $5 and tossed it when I arrived at my destination (I wasn't flying back).

Good idea on the shrink wrap. Heavy duty food wrap can substitute, or a trash compactor bag and good packing tape.

We took a cooler to Maui to use in the car for picnicking and packed it like luggage and taped it up. The poor Hawaii agricultural inspectors had kittens until they saw it was just full of sandals and beach towels.