You have a range of choices. Lately I've tried a thread called EZ Line. It's pretty cool stuff. It is elastic to several times it's original length, it is black, and it superglues well. Drill a tiny hole, like a "50" for one end, stick it in and touch with a tiny bit of glue on a toothpick tip. Pull just a little and either wrap the other end around where it goes or just hold it against that point and glue it again. Almost right away you can let go, and trim later. I can fly along with the stuff. It is scale too thick for this ship, but anything scale would be pretty invisible.
Also once installed, you can snag it with tools or fingers and it stretches and returns rather than snaps off.
Oh, and work from the inside out.