Here's something you could do:
1: Buy some white tissue paper.
2: Tape a rectangular piece of tissue paper to the edges of a normal piece of paper
3: put it into a printer like you would put a normal piece of paper.
4: print out a design of scale remove before flight tags onto the tissue
5: Cut the remove before flight tags from the tissue paper after you are done printing them
6: Use them on your model as you wish!
Or for an even easier way to make remove before flight tags, you could just draw them straight onto the tissue paper with pencil crayons, but don't use felt because it WILL bleed all around the tissue paper into uneven blotches.
I hope this helps,
Rob