Remember how RRs died of belly flops? Well, it's the same for alpines.

rebase: "Dragons cannot fly leashed"

Explain this better. Dragons that are physically unable to fly (with exceptions) are meant to take fall damage

Alpines (obviously) are able to fly. If you leash one it automatically goes into landed mode, and when it reaches the ground it takes fall damage, similar to how RRs used to take fall damage if they were knocked unconscious in the air.