There are blunt scissors on the market that you can take on a plane. As for cutting thread: the Clover pendant has a integrated tiny blade that cuts thread perfectly. As for your rotary cutter: that has to travel in your checked bag, otherwise the security people will have heart attacks! They don't have any sense of humor!!
I guess that means you have to take either handsewing on board - or a book!
Have fun!
Tirolgirl