Howard Hawks, the notable US golden-age film director had trained in the US' Army to go to Europe as a squadron commander, but the war ended before he went overseas. He had other stories of his experiences later, including this one, taken here from the website '
Parallax View', of a 1976 interview with Hawks.
"One critic said that usually I was pretty much to be relied on, but when I made a picture called Only Angels Have Wings, now that was just too much for anybody to believe. I wrote him a letter and said that—I kept a copy of this letter and I’m thinking of publishing this letter—every single thing in that picture was absolutely true, there wasn’t anything I invented. I invented how to use it. I got back a very nice letter.
"The whole story was about … I was down in Mexico hunting with a bush pilot. You know, there weren’t any landing fields; they land anywhere. He had some homemade things that he dropped, and smoke would come out, and he could see which way the wind was blowing. And we’d go down and land and run our wheels on the ground to see whether it was mushy and marshy or what. And I went to dinner, and there was a guy there whose face had been burned in flying. All scarred. No expression on his face. Just talked to ya—nothing happened on his face. There was the cutest girl. The dinner was for a pilot and this girl. They were married, and they met in exactly the same way that the two people in Only Angels Have Wings met. And the only thing I couldn’t use was the fact that the fellow with the burnt face got up and said, “A year ago tonight you were married. You went to bed about ten minutes to two. You got up at two o’clock. There was a pause of about 15 minutes, then you repeated this thing,” and the girl said, “Damn you, you were peeking!” And they brought out a German machine used to keep the hours on flying; and it recorded when the motor started on a scroll, it recorded the takeoff run and recorded in the air, change of altitude, and landing bumps, so that they had a complete record of the time. And he’d hung it under their bed. Instead of being angry, the girl was so pleased and so proud of it, she put it up over the fireplace…."