Here's my plan when airships arrive:

Start doing the majority of my leves in Grid. -- The reason for this is because prior to Chocobos (which is now) the easiest method for leves at R40+ are tele to BW, walk up to Halitali, and finish with drybone for my low ranks. With a choco, the walk takes a lot of time, making the distant r40 nodes seem like less of a hassle. And Grid has the marks that i want.

After, I will airship right on over to LL, where I will do all of my Grand Company stuff, like caravan escort. I'm not fearful because if I can easily transport there, so can everyone else.

Then I will finish by going to Uldah, where the market is centered. I don't foresee people moving their shops over, but it doesn't really matter because getting to each city will be a breeze.