@Lightsaber70 i fixed the plane, longer hull, removed the top wing and some other changes. i uploaded it and it flies really well, no need to check it out but it would be nice.

Nvm that last comment, just use the reconnect tool. Last comment as in the one I posted seconds before this one, if you didn't see it, don't worry about it, just use the reconnect tool on the tip of the strut. Another edit, noticed the bottom things where also wing blocks, same fix as the other wing blocks.

@prankstergangster360 No problem, mate, no mistakes in your response either, my dude.

@Lightsaber70 first of all i appreciate your help to make my planes less bad. i didn't make any landing gears because i was a little bit frustrated with these planes not taking off, for the others things you mentioned, thanks, i will try to make the plane longer and do something about that wing piece. i do not know how long it will take but i will try. for the time being thank you (don't know if there are any mistakes, i'm dutch)

Ok, so, I noticed a few things with the design that may be causing your issues, for one, none of the squadron aircraft have anthing to keep their tails off the ground during takeoff, leading to them kinda derping around on the runway. Two, for the top wing, I noticed you used wing parts to connect the two, this is going to sound wierd, but that does screw with the aerodynamics, instead use structural panels, because the individual wing blocks shift around(because SP physics), it will shift the COL, causing the plane to pitch up or down uncontrollably. One more thing: I'd personally recommend extending the plane so you can add tail landing gear.