To Reproduce
Steps to reproduce the crash:

1. Add flans mod to forge server with ww2 pack
2. place a plane or two
3. join back
4. client should crash (at least for me)

Screenshots
N/A

Versions (please complete the following information)

• Forge: 1.12.2 14.23.5.2854
• Flan's Mod: 1.12.2 5.10.0

Crash Log
https://gist.github.com/thereal123dprinter/a4fcc70a9f0f09936be7674a9a42054f

Additional context
Any way to despawn placed vehicles? I believe that if I removed them that I would be able to play normally.

Also, it only crashes if you are in close proximity to the vehicle causing the problem.

A quick solution to remove the vehicle would be to remove them from your content pack. That way when the world loads again it would probably simply delete the vehicles. But make sure to create a backup of your world first!