Answer: It's known as the continental drift :)
Explanation: "Pangea's existence was first proposed in 1912 by German meteorologist Alfred Wegener as a part of his theory of continental drift. Its name is derived from the Greek pangaia, meaning “all the Earth.”" (copied from google)
Methane, overview, carbon dioxide, Fluorinated Gases
Initiation, elongation, and termination
Answer:
The air would be too thin for most helicopters to create enough lift to remain airborne. And if somehow a helicopter did make it up there, landing wouldnt be easy.