put your block in a flat storage container and the thread, needles, small trim scissors ( blade must be less than 4" to bring on board). I carry a pair of fold up scissors when i travel. They don't even look like scissors when they go through the scan and i've never had an issue with carrying them. all this can fit in a pocket of a tote or laptop case. my carry-on is my photo gear bag ( a specialized backpack with a laptop section and my Featherweight sewing machine in a portable carrying case.