http://www.ospreytravelpacks.com/packs/48/

I traveled in Spain in May for 2 weeks using this Porter 46 because it fit
in the overhead bin of the aircraft. No checking luggage and no waiting at
the carousel for your luggage to arrive after you.

Great bag. I also got the daylite bag.
http://www.ospreytravelpacks.com/packs/61/ You just hook in on the outside
of the Porter and you can detach it and use it as a day bag later on.

Pat in TX