When your plane goes from safely and securely on the ground to flying in the air, that transition can actually be pretty challenging. Just a moment ago your tires were on the ground and you were in pretty good control of where you wanted to go. Suddenly you're soaring through this fluid atmosphere that has it's own ideas of how you should be moving around. Transitioning from that familiar ground-state to riding the air currents can be... challenging. 

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DISCLAIMER:

I am a student of aviation, and a new one at that. Therefore, I make no claims to being an authority of any kind on the topics that I talk about. I am only speaking from my limited, biased perspective as a student who is learning and making mistakes. Therefore, none of what I say should be taken as fact or advice to be followed. Double-check me and let me know when I get it wrong.