It has been 10 years since I have flown. I used to carry merry-go-round organ pipes and mechinisims, as cary on. Used a cardbord box the exact size of under seat compartment. (Openable of course.) one time the Pilot asked me if I brought the Donuts. (which go good with Bacon and eggs.) The TSA guy said I was bringing "industrial clamps." according to his X-ray.