The question is how you react to that, and offering to acknowledge the presence of the other and to find out their wishes regarding the flight is the common sense thing to do.
Only for an extrovert.
In the end, even to an introvert, simply stating "Oh hello, I'm so and so, unfortunately I have a lot on my mind, I'm sure you understand" isn't outside the bounds of the reasonable. Do you disagree?
Yes.
As someone who has been "trapped" in dozens of conversations with someone seemingly nice but uninteresting it's surprisingly hard to straight up tell someone you don't want to talk to them. I
r/Fitness does a weekly "Moronic Monday", a judgment-free thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. I thought this seemed like a useful thing to have here - after all, the concepts discussed on LessWrong are probably at least a little harder to grasp than those of weightlifting. Plus, I have a few stupid questions of my own, so it doesn't seem unreasonable that other people might as well.