This works better as a movie than it does as history or science, the leads have chemistry, it's often beautiful etc. But even as a movie it causes you to raise your eyebrows at the unlikelihood of some of its characters and actions in that era. And some of the liberties taken with the actual facts of the history make me kind of glad it didn't do better so as to not encourage this sort of nonsense.
As history we get some more classic Hollywood arrogance, where with barely a nod toward "Based on a True Story" they completely write out of the film a real historical figure who accomplished something pretty major (a man named Henry) to invent from whole cloth an anachronistic female heroine named Amelia who is never believable for that age of history. Imagine if somebody wanted to make a movie about the Wright Brothers but decided that really it's so chauvinist that they were both men so let's just change Oroville into a woman and make her the brains of the outfit.
And I was particularly amused when they finally launched their balloon that the filmmakers decided, with not one apparent sense of unease, that they would make their adventurers reach 36,000 feet in the air, in a balloon, without any oxygen, and barely any protective clothing. That's taller than Mt. Everest where people bring oxygen tanks and wear parkas, its higher than commercial jets fly, where if they lose pressure you will freeze, suffocate (hence little oxygen masks) etc. But our film, allegedly about a scientific achievement, can't worry about such scientific technicalities.