Your Friend Is a Troll
Just so you know, some people think the Earth is flat. Humans have discovered the roundness of the Earth over 2,000 years ago, yet some people still think there’s no way anyone can prove it. So, the OP decided to ask their new best friend, who just happened to be a pilot, to provide them with the truth.
Instead of trying to convince the OP, the pilot friend decided to just go with it. They claimed that they were bound by their pilot’s license to never reveal the flat shape of the Earth. But for some reason, they decided to tell one person, whom they hadn’t seen in a long time. See how gullible the OP is?