Anytime this conversation comes up lately I ask the people to imagine what it would look like if planes were flying over a stationary, "flat" plane. What would be different, or what we would do differently on a globe.

You would take off the same way, fly exactly the same way, and not adjust for a constant drop in altitude... Exactly how it all goes when we fly.

It's this cartoonish idea of what they put in our heads that keeps people believing in these silly ideas.