Hey Adam — Thanks for this great feedback. What you say really points (I think) to a cultural assumption I relied on without noticing. I did not spend any time at all working out the psychology of this scene, but looking at it based on your question, I think I see what I might have done unconsciously. Let me see if I can tease it out…
The father was not ready for his son to grow up. He had prepared his son over many lessons, trying to instill in him the importance of taking the responsibility of driving seriously. I tried to convey (at the end, with the punchline) that the father had spent many sessions with the son teaching everything he could about driving. I framed this scene to only the “pre-flight” check list.
But when it came down to actually driving this would mean his son had moved beyond childhood. The father was not yet ready for that transition. Faced with admitting that his son was becoming an adult who could take on adult tasks, the father retreats.
BUT — he does not lie to his son, saying that the son is not ready. He admits that it is he who cannot take the next step. The father is the one who cannot let his son “fly”. So he stops the lesson abruptly, but says that it is his problem, not the son’s.
Maybe I stretched believably here, but that’s where I went without a great deal of thought and absolutely no rewriting.