How about planning and precutting a wall hanging?
Think handwork, a hand made project like making funky applique blocks. You can carry a good sized stack of precut blocks in a plastic ziplock bag. A package of needles, a few spools of thread, something the allowed size to cut with...
I like projects like 3D bowties, hand stitched together to make the blocks, and then the blocks stitched together in rows to make a quilt top, that goes amazingly fast.
Do you have a handmade UFO?
I think carrying a machine might be more of a bother, but actually, I carried a small 15 pound machine while traveling in europe for about six years. So who am I to give you advice? I used it for small projects like placemats, and other gifts like pretty bags. I still have it and carry it to use in classes but there were no restrictions then.