James Cameron was very much running out of interesting things to say and show in his “Avatar” franchise with the second movie, “Avatar: The Way of Water.”

The third film, “Avatar: Fire and Ash” confirms that fear and adds on a dose of dread for good measure. On no, the 70something sci-fi impressario has two more “Avatars” in the works.

And as often as the latest film pauses to show us this or that mode of travel — riding Pandora’s version of pterodactyls through the skies over this lush lunar ecosystem, clinging to the fins of sentient, hunted Pandora whales under the sea — will Disney be able to make rides simulating the experience that would be a draw?

The three-hour-plus spectacle of “Fire and Ash” trips over itself, start to finish. Our villains (Stephen Lang plays their leader) keep surviving in Avatar form, keep catching “Sully” (Sam Worthington, who hasn’t gotten better with the years) and ineplicably letting this “traitor” Marine who’s “gone native” escape.

There’s still more mineral and animal exploitation by the corporate “Sky People” from Earth who mine it, hunt and are building a bubble city as a colony, since no one on Earth can breath the planetoid’s poisonous atmosphere. But the villains (Giovanni Ribisi, Edie Falco and Lang) seem kind of half-hearted about their efforts this time.

The marine biologist (Jemaine Clement, never worse) who warns of the complexity of the eco-system they’re pillaging is no more convincing this time.

Jake Sully and his tall, thin and testy Na’vi “woman” (Zoe Saldaña) are still mourning their lost son, half-blaming their surviving son and somewhat appalled that the orphan Sky Man lad (Jack Champion) they’ve taken in, the weakest link in their family (he’s short, human and has to wear an oygen mask) is magically enabled to breathe Pandoran air.

If humans can breathe, it won’t be long before they overpopulate and pollute that air and kill off the natives.

There’s a new Na’vi tribe lead by a warrior/conjure woman (nepo baby and grandbaby Oona Chaplin) who hunts humans and weaker Na’vi alike.

“Show me how to make THUNDER,” she demands of the Earthlings and their automatic weapons.

Yes, there are chases and firefights and battles, captures and escapes. No, there’s no allegory connecting all that to the awful state of the Earth right now save for the fuzzy environmentalism being ignored.

The mystical Authrian mumbo jumbo about the people, the plants and the planet being “one” is hinted at time and again, mostly in the filler scenes between brawls. The eco-system fights back theme is more overt, as are calls for pacifism.

But “Avatar” wouldn’t be much of an action movie if pacifism caught on.

The novelty of Signourney Weaver playing a teenage-voiced CGI version of herself as a Na’vi/human clone wears off quickly. But the CGI blends so much more smoothly in this film that Champion — as a human only seen in human form — is plainly acting and interacting with the CGI/motion captured players he shares scenes with so naturally that we don’t notice the technology as much.

It’s just that the performances have run out of human and digital gas. Even the over-acting is wooden, and bits intended as humorous suggest taht Cameron’s been on the soundstage and mo-cap green screen stage too long to remember what funny looks and sounds like out in the real world.

The story is boring, and dragging it out for over three hours will only make it tolerable when it hits streaming.

“No dear, don’t pause it while I duck into the kitchen to whip up some Eggs Benedict. I’m sure I won’t miss anything.”

I’d suggest waiting until this streams, or becomes a theme park ride. All this world-building is pretty much coming to naught in movie form.

Cameron’s run out of interesting things to show and tell us, and Goddess Eywa knows I’ve run out of things to say about “Avatar.”

Rating: PG-13, violence, nudity, profanity

Cast: Sam Worthington, Zoe Saldaña, Stephen Lang, Cliff Curtis, Sigourney Weaver, Jemaine Clement, Jack Champion, David Thewlis, Giovanni Ribisi, Kate Winslet and Oona Chaplin.

Credits: Directed by James Cameron, scripted by James Cameron, Rick Jaffa and Amanda Silver. A 20th Century release.

Running time: 3:17