That is true but only when you’re in the cargo ship going to Lindblum for the first time. Other than that I don’t think the lovely people at Squaresoft at the time really cared about this one small continuity error
And it wasn’t just airships which used Mist for power; much of Lindblum’s technology seemed to depend on it. For instance, if you go back to the Cable Car station at South Gate in disc 3, one of the attendants next to the carriage mentions that the Cableway is out of service because the Mist has disappeared, which the Cable Car is powered by.
However, the Mist didn’t totally disappear – Kuja himself mentions that Mist remains in valleys and caverns, so I guess that’s how Lindblum’s Aircab fleet along with the Lindblum Castle elevator and trolley were all able to keep running in the meantime – probably supplied with Mist in tanks or something. Or maybe I’m reading too much into this… :p
Hmm, that’s not a good sign. I blame the HSC for completely draining my mental power