Had a crate made to for air/road freight moves instead of baggage.
Weights 15kg/33lb, inside dims 80x30x65cm (31.5x12x25.5in). Not light but no-worries strong and fits Brommie/Birdy standard fold with lots of space for other stuff.
Next time around I'll get it down to 10kg with better communication skills.
Do you store the crate at the airports then when you travel?
No, it is packaging through to delivery at destination. For a short return trip one would use a suitcase or original packing carton and move as baggage. The crate is for freight mode.
Oh sorry silly me! What suitcase do you use for your folder?