Recently played the latest Demo and here'll be my two cents.
Gameplay is really, really fun. On hard mode it's a mix of fun and challenging; as for easy and normal, I never got to try them so I don't know how easy/hard they really are. I like the airships that appeared in the second scenario, and the design reminds me of Ace Combat 6's Agaion and Kottos/Gyges command cruisers. Their presence at first gave me some shock and awe, though I thought they were B-2s at first. Their HPs aren't too bad, just right in terms of their size. The appearance of large numbers of enemies in the last phases of scenario 1 and 2 may give newer players a bit of shock, but Ace Combat players will feel right at home dodging and weaving through enemies and missiles.
The semi-fictional way you named real aircraft kind of weirded me out at first, but then you probably need permission from aircraft companies to use their aircraft names in-game. This may be perhaps your opportunity to create fictional, albeit aerodynamically sound aircraft for the player to use in-game.
In terms of details, it's a big improvement compared to the last demo. Sharper textures all around and much better-looking nozzles (Love what you did with the Flanker's nozzles!). My one complaint is that while the ground textures look much better, they're in need of optimization. Whenever the camera looks down onto the ground, my FPS drops from 70-80+ to 40-50 fps (on a GTX 1060 and i7-6700HQ. 16GB RAM).
Overall, it's a great game with great graphics, though may need some optimization here and there. I'll give it a good 9/10.