How do I do it for an engine?

@Razr check out my newest plane

Your welcome, what are you making @Scythesinister

@Razr It works! Thank you very much for the help

@Razr no, it doesn't allow that to prevent copies... see?

Take the cockpit off, the whole creation should turn grey, and drag it up to the subassemblies button (If there is multiple cockpits, it won't work)