I am actually working on 2 approaches: a model plane like the one in the picture above, dev-looking with color tint on the controls you are using - ailerons, flaps, elevator, rudder, basic shapes for the guns and projectiles so that anyone can pick-up from there and apply it on their own models; also a realistic textured and modeled airplane on a terrain with small features. The latter feels a lot better though it’s the same framework behind it - just different visuals.
However all this happens late at night when I have some spare time. I wish I had some more time for unity and I also wish I could afford the pro so I can complete my forest project (without occlussion culling I don’t see how I can test that one);
At the moment my aircraft behaves realistic. With a few tweaks here and there. I too have a button for stopping in mid-flight - or full stop while rolling on the ground (an early brakes control) but I added a rough stall to it - without the visuals (it doesnt spin yet) but it falls on the ground. IN short, the controls need little tweaks.
I also added visuals to the controls mentioned before (aileron, rudder) so they behave like they should in flight - if I climb, the ailerons will rotate up, if I climb/turn left - the right aileron goes up whilst the left rotates down and so on. For the moment I don’t have those rotations smooth - although I managed a small script that does what I need - it just take a bit of time to understand what’s what when setting up the entire plane rig.
I also added wheels. When you taxi on the runway, the wheels spin accordingly and in mid air after a while they stop. It’s rather funny to see the plane jumping a bit from terrain features before taking off (wheel springs);
Things like contrails at a certain speed, speedmeter, altimeter (gauges not numerical), audio fixes, audio on different impacts, these are small things and almost completed.
Early on I had implemented a cockpit camera as well with a 2D cockpit; A few things changed but I might add it back (though it requires either 2d or a full cockpit and i simply don’t have that time); I have a rough propeller in place - meaning it changes from a model slowly spinning to a plane with a ‘full speed’ propeller and back - just need to tweak speeds there. Things like lights on the wing tips are really simple to do. You could say that the aircraft kit can be used for a project like x-plane; it just needs a lot of settings / plane because there simply are a lot of features.
The plane has also a basic health (without respawn because it would go beyond the scope of the kit) and weapons. The machine gun needs a better audio but the rockets and bombs are quite fun.
And finally the aircraft crashes in a realistic way. Controlled with a separate very simple script, you can have the aircraft smash into bits and pieces with smoke, fire, audio effects and whatever else.
I had a rough EIffel tower model placed in the scene and I must say its simply delicious to fly around or under it. Not to mention crashing into it and watching the wreck going down in flames.
I could put up a demo right now but people are picky; I also want to complete this on my own just to prove how good unity is 
I’ll have a demo in a day or two here.
Regards
