THE AERONAUTS: Up, up and away ... in this beautiful new movie

Since “The Aeronauts” is supposedly “inspired by a true story,” viewers will wonder whether its best and coolest scene ever actually happened. And the answer is:

Sort of.

In this entertaining new film about the early days of hot-air balloons, the adventurers’ release-valve gets frozen shut at 30,000 feet; so pilot Amelia Wren must climb the icy netting, right up the side of the balloon and onto the top, in order to bang it open -- otherwise, the craft would just keep on ascending toward space. This dandy scene is paralyzingly effective even when streaming on TV; I can’t imagine what it looks like on the big screen.

But it didn’t exactly happen that way.

The maneuver was actually performed by a man (Wren’s character is entirely fabricated for this film). And he merely climbed into the hoop to wrestle with the jammed mechanism -- though as here, he did do it alone, since his fellow-ballooner had passed out from oxygen deprivation; and like Wren’s, his poor fingers were so frozen that he barely managed to complete the fix and get back down.

That other intrepid traveler is one James Glaisher, who really did pioneer hot-air exploration in the late Victorian era, taking meticulous measurements and greatly advancing our knowledge of meteorology as well as the upper atmosphere.

An Amazon original that is now available online, “The Aeronauts” reunites “Theory of Everything” actors Eddie Remayne and Felicity Jones as Wren and Glaisher. It’s exciting, well acted and absolutely gorgeous.

Besides its unforgettable climbing scene, “The Aeronauts” features much other airborne panic -- some in a terrible storm that flings the basket every which way, and then at the end when Wren and Glaisher are descending too fast and must scramble to avoid a crash-landing.

The two actors -- both excellent -- actually did execute a lot of these nerve-wracking mid-air feats, including one brutal and unexpected touch-down that nearly killed Jones.

While these scenes work exceptionally well, viewers will also relish the movie’s luscious visuals. In shot after shot, in clouds and sun and snow and storm, you almost want to pause the film just to bask in the picture-postcard beauty.

I’d expected the story to involve several trips, but “The Aeronauts” confines itself to Glaisher’s best-known attempt, when he and his brave assistant, Henry Coxwell, soared as high as 37,000 feet. Which is pretty impressive, as it’s two miles higher than the point where oxygen loss begins to cripple both brain and body.

In order to sustain interest over the length of this single voyage, the script employs a flashback format, layering in stories of Glaisher’s struggle to sell his work to investors -- and of Wren’s earlier attempts with her late husband, who died during one of their ascents.

Though only a little of it actually happened, “The Aeronauts” is grand cinema. Viewers seeking the facts might look up Richard Holmes’ acclaimed nonfiction book “Falling Upwards,” which served as the basis for this film.

* * * (out of four)

“The Aeronauts,”

directed by Tom Harper

Run time: 100 min.

Rated PG-13 for a little blood and considerable peril