Betty Grable was considered for the Gene Tierney role.
Robert Blake, adult actor of "Baretta" fame, plays Chandu, boy sidekick of George Montgomery.
Kunming, China was the home of The Flying Tigers.
Even though, Gene Tierney plays the title role, she actually doesn't show up until 19 minutes into the film.
Even though the Flying Tigers were organized as a volunteer-staffed mercenary air force earlier in 1941, they never flew in combat until December 20, 1941, two weeks after the U.S had entered World War II following the December 7th Pearl Harbor attack. So in spite of the film's plot, there was never a time they were flying in combat and the United States was still neutral in that conflict.