In 1785, Jean-Pierre Blanchard demonstrated using a parachute as a means of safely disembarking from a hot-air balloon. While Blanchard's first parachute demonstrations were conducted with a dog as the passenger, he later claimed to have had the opportunity to try it himself in 1793 when his hot air balloon ruptured and he used a parachute to descend. Jean-Pierre died from injuries sustained when he fell from his balloon after suffering a heart attack, in 1809. His wife Sophie continued as a solo balloonist after his death. Sophie Blanchard was known to dress distinctively, as to be seen from a distance, gave parachute demonstrations, and specialized in night ascents and fireworks displays. On 6 July 1819, her hydrogen-filled balloon caught fire and crashed into the rooftops of the Rue de Provence, Blanchard fell to the streets below and died. She is buried in the Père-Lachaise Cemetery in Paris. Her tombstone that still stands, was paid by a collect money from the French public and shows a sculpture of a burning balloon and the inscription "Victime de son Art et de son Intrepidite" (Victim of her Art and Intrepidity).
James Glaisher was a real English meteorologist who is remembered for his pioneering work as a balloonist. Between 1862 and 1866 he made numerous ascents to measure the temperature and humidity of the atmosphere at its highest levels. With his co-pilot aeronaut Henry Tracey Coxwell, they broke the world record for altitude on September 5, 1862. Coxwell is omitted from the film, and replaced with the fictional Amelia Wren. The Wren character draws some inspiration from various real women most significantly Sophie Blanchard, a French aeronaut who was the first woman to work as a professional balloonist between 1804 and her death in 1819.
The flight takes place in real time in the movie.
Eddie Redmayne was injured filming a scene on the air balloon and badly sprained an ankle. He had to use a crutch and a cast for a few days.
Rare for a period picture nowadays, Amelia is correctly shown with unshaven armpits (women didn't really begin shaving until the 1910s).