So I got to thinking about crafting airships, from the Cid perspective, from that corporate and main storyline perspective, and the Beast Tribe perspective. There has been speculation about Free Companies having the "slot" at their houses to dock an Airship, and discussion about whether crafters will be able to build airships.
I think completing the Ehcatl Quest should be the general "requirement" for crafting airships, since it provides us with recipes, although I don't think after we complete the quest, we should be stuck with the quest restrictions on cross class abilities, CP sync down or special forges, and we would have to supply our own materials.
Additionally, we might have specialized options for Airship parts from each class, so each company's airship might have some custom features, similar to houses.
I'm sure there's more input on this than I'm aware and would love to hear feedback!