The model came with a 2" x 120" crepe paper streamer. I've been flying mine with that same size for years and years. most crepe paper is already flame retardant so it fits very nicely in the space provided
I learned a long time ago to fold and roll these crepe streamers to ensure they open promptly.
half them, then half again. then one more time then roll the last fairly tightly to fit the body.
NOTE! once all the pleating has been squished out of the crepe paper they no longer catch air and chould be replaced with a new one
Hope this helps.