IIRC it is physically impossible to do that without server-side mods.
However, 1.18 has a 319 block limit which I know will be the limit when CCNet updates to 1.18.

It's impossible to increase movecraft size? Tf?

No it's not impossible

And you can make fighters look quite good without 300 blocks,your choice to make them look like box. 300 blocks should be for bombers as they were larger in size

now your speaking my language