I would love to see this movie on TCM despite the flaws that you point out. And yes, I could probably appreciate Mr. Montgomery a bit more if I thought he did a role in this writer's work some justice, though the translation of this work to film sounds a bit shaky from your description.
Saint-Exupéry looked at life and the adventure of air travel with a poet's eye, and his writings on life in the desert were particularly vivid. If anyone ever wants to know what it might have been like to fly when aviation was new, Wind, Sand and Stars is also one of the most emotionally informative books I've ever read on that period, seen through Antoine's eyes. How sad that link to the Telegraph story about the German pilot being discovered who had shot this beautiful writer down. But, at least we have this man's words, such as those below:
"We don't ask to be eternal. What we ask is not to see acts and objects abruptly lose their meaning. The void surrounding us then suddenly yawns on every side."

The real Antoine