My friend flew with her small machine recently, and she still had the original packaging for it, which fit within the airlines carry on limits. She then packed it into a small tote bag.The scanning folks kept sending it back and forth, and calling other staff over etc. Finally they asked her - "This looks like a sewing machine, are we right?" She just laughed and confirmed, and they opened it up. I guess for this bunch, it was their first time ever seeing anyone "carry on" one.