In the opening scene at the bar, one of the women raises her glass to her mouth, then in a close-up the glass is near her stomach and she raises it again to her mouth.
Aviators in World War I generally didn't wear the high-collar tunics like the one worn by Thad. This is because they needed to be able to turn their heads while flying. Rather, they wore a uniform coat that required a shirt and tie.
Several aircraft are parked in the background of the airfield. When Bill Wellman takes off for his first solo flight, he passes over three of them, which are revealed to be flat, painted cutout silhouettes.