Does this ring any bells? The airships were plant forms that floated and could be used for transportation. There was a diverse cast of characters on some quest, including some sort of psychic centaur-like creature.
It has the living airships:
“That’s our way off this cliff,” he said. “His name is—” he pursed his lips and whistled three clear notes with a warble at the end, “—but I see that’s awkward to use mixed with English. I call him Whistlestop.”
“You call him ‘Whistlestop,’” Cirocco repeated, numbly.
“That’s right. He’s a blimp.”
He looked at her oddly and she gritted her teeth. “He looks more like a dirigible, but he’s not, because he doesn’t have a rigid skeleton. I’ll call him and you can see for yourself.” He put two fingers to his lips and whistled a long, complex tune with odd musical intervals.
And the centaurs:
The Titanide found them while they were taking down the tent prior to moving Bill. It stood on the top of the bluff where Cirocco had been the day before. Cirocco waited for it to make the first move, but it seemed to have the same idea.
The most obvious word for the thing was centaur. It had a lower part shaped like a horse, and an upper half so human it was frightening. Cirocco was not quite sure she believed in it.
It was not as Disney had envisioned centaurs, nor did it have much to do with the classical Greek model. It had a lot of hair, yet its dominant feature was pale naked skin. There were great multi-colored cascades of hair on the head and tail, on the lower parts of all four legs, and on the creature’s forearms. Oddest of all, there was hair between the two front legs, in the place where a decent horse—which Cirocco’s mind kept trying to see—had nothing but smooth hide. It carried a shepherd’s crook, and but for a few small ornaments, wore no clothing.
The Blimps and Centaurs "speak" a very music-based language, but it's hinted that it may have a telepathic component.
The first book, Titan, is a fairly straightforward adventure story. The second book, Wizard is more of a "quest" type of story. The last book, Demon is a post-apocalypse/revolution/war story with a little social commentary thrown in. From the OP's question it sounds like they may only have read the second book. Although the third book has more of the post-apocalytic events, it also has a... larger-than-life character that would be pretty hard to forget.
I believe this is Dark is the Sun, by Philip Jose Farmer. It's set in the very far future, the characters travel in/on a giant plant pod for part of their adventures, and one of the characters is a plant-centaur shaman with psychic powers. The group of main characters were trying to recover their stolen 'Soul Eggs'.