John Hodiak died suddenly one morning just before heading to the set to film one of his final scenes for this film. He had suffered a heart attack.
Hodiak's character had his blood pressure measured near the end of the film, 128/80. This is a very good BP, one that would be expected in the military. In reality, Hodiak suffered from hypertension, which kept him out of the service during WWII and killed him just before wrapping up production on this film.
Guy Madison's normally hairy chest was completely shaved for his two beefcake scenes with co-star Virginia Leith.
Balloons were flown to extreme altitudes in Projects Manhigh and Excelsior, starting shortly after the film debuted. In the latter, then-Captain Joseph William Kittinger successfully completed a jump of 103,000 feet, free-falling for more than 4 minutes with only a small drogue chute, something similar to a kite's tail, to prevent him from spinning. Despite suffering severe bruising from the extreme low pressure trauma experienced at that altitude (similar to "sea" level on Mars), and frostbite from the extreme cold (almost 100F below zero) Kittinger was none the worse for his dangerous adventure.
This was the second aviation movie to be filmed in part at Eglin Air Force Base in the Northwest Florida Panhandle - Der Kommandeur (1949) was the first - but the 1955 appearance in nearby Fort Walton Beach of Guy Madison never generated the same level of interest as Gregory Peck had, according to 1955 coverage in the Playground News.