(Just a filler upload for today to show I'm not dead.)
Here it is, just bird wings slapped onto a jet body.

I knew it was definitely possible to make ornithopters in SP, but here is my second (we dont talk about the first) attempt to create a functional ornithopter.
It controls pretty well, and flies very easily.
Oh yeah, it is a little hard to take off from the ground... I'll provide instructions later.
Otherwise, it has a realistic flapping motion for the wings, and throttle controls the power behind each flap.
There's also a small jet engine to help with acceleration, but its not too powerful.
At 0%, it allows you to glide, still easy to control and will settle at around 64 mph without input. Not sure why that is.
It's fun to fly! very arcade-y. just roll to turn and pitch to... pitch.

For the takeoff, pitch the nose all the way up, then increase the throttle SLOWLY to 50%. At around 60 mph, increase throttle to 100% and lift off the ground

Or you can just hit 100 right away and slam the wings into the ground. Your choice.