Other mistake: When Lindbergh is forced to parachute out of a stalled plane near the beginning of the movie, the plane goes into a spin. It crosses the screen twice, first below Lindbergh's parachute and then above, indicating that Lindbergh is falling faster than the plane (which is possible, since the plane is spiraling rather than falling straight down). However (as indicated by the loud noise heard off-camera), the plane somehow manages to hit the ground first.
Factual error: Before Lindbergh takes off a woman gives him a small mirror to use to read his compass in his plane. After he takes off the woman is seen on a train going home. In the window behind her you can see the Pulaski Skyway. Lindbergh took off in 1927 but the construction of the Pulaski Skyway didn't start until 1930.
Trivia: Jimmy Stewart was not the first person picked to play Lindbergh. Stewart at the time was in his mis-40's. The first person at the time the same age that Lindbergh was at the time in 1927, But the actor had been fired by the studio a few days before filming began. His name was Clint Eastwood. Stewart had to lose 25 pounds of weight and dye his hair light brown.