I don’t recall the instances in TaleSpin that you’re referring to. But it’s worth noting that TaleSpin Kit and DuckTales Kit are different characters from different continuities. Among other things, one was a preteen in a fictionalized 1930s, whereas the other was likely the same age in the 1990s. There are doubtless many other differences between the two.

2017 Kit probably just lacks natural talent as a pilot. He has only so much ability in that area, beyond which he cannot progress. His rather careless approach to business and life in general may also have negatively impacted his performance.