Well, I'd call it at least TL9 for the purpose of practical uses. Remember that flying toys have been around since ancient times (such as this early Chinese
bamboo helicopter), so I have no problem allowing tiny applications to exist before a full-scale design is close to feasible. It is unfortunate that Spaceships 7 doesn't give an alternate TL for an Ultra-Tech ornithopter though. Especially considering that the quote right next to the system description is from Dune, a decidedly UT setting (if somewhat anachronistic at times).