Surface id 178 seems to let aircraft vehicles fall through

[LosFaul]

Describe the bug

While working on custom maps i figured out by accident that col sufaces with id 178 let aircraft vehicles fall through
when there is no driver inside
this bug seems to only affect aircraft vehicles

To reproduce

create a custom model and change all col surfaces to id 178
spawn an aircraft vehicle for example hydra or hunter and you will see it will fall through when there is no driver in it

Expected behaviour

aircraft vehicles don't fall through

Screenshots

Version

Client: Multi Theft Auto v1.5.7-release-20664

Additional context

I could imagine that this bug might also extend to other col surface ids

[Vadya963]

I don't think this is a mistake

[Vadya963]

I also make a custom map, and met the objects of the GTA itself, where they were without collision for cars

[LosFaul]

update:
i figured out it has nothing todo with col surface id
but it rather seems to be some model flag that causes airplanes to fall through

so i could imagine that this issue might be solveable when:
#1714
is added in the future