I fly with my Featherweight all the time. I have a soft Jean Lyle case for it, which you can see at
http://www.jslyle.com/accessories.htm . The machine goes on board with me and I stick it in the overhead bin. It's very light and easy to carry around in this bag.
Although last month in Toronto, airport security took the screwdriver away from me.
(I'd flown with it from Vancouver, no problem!) The stupid thing was that they let me keep my incredibly sharp, pointy tweezers, but the large, blunt, slotted screwdriver was verboten.
Anne in Vancouver, Canada