I'd like to start by saying I appreciate you not instantly insulting those with the FE mindset. While I myself am RE I believe I can answear your questions.
I didn't come here to bash, nor did I come here to tout about one belief or another. My objective is to learn, and only that. And through that maybe I can discover my own beliefs

I think people that are automatically attacking a belief or idea are full of S*** and they need to learn to at least tolerate differentiating opinions.
Cant remember who said it in their book but this is my mindset with tolerance "When faced with the persecution of my group (the author was in a Nazi prison camp), first the Hindu's were taken and killed. I said nothing as I was not a Hindu. Then the Gypsies, I said nothing because I was not a Gypsy. Then the Jews, I said nothing because I was not a Jew. then the Christians, I said nothing because I was not a Christian. Then they came at me, and when I cried out, I had no one left to help me." We should never discriminate against a belief because you never know when it will be their help you need.
Answear 1) My own idea on how this would work is that our eyes have a set distence with which we can observe objects through our atmosphere. The distence is the same in all directions, which means our line of sight ends up being a circle. This could (if viewing the world from a high altitude) result in the appearence of a curved horizon. Others may post other opinions.
Never thought about that before... I'll have to research it.
Answear 2) On the FE model, the north pole is in the center, while the south pole makes up the outside edge. If you base navigation on a compass you will always be traveling East or West, which is left or right of North. This would cause you to travel in a large circle around the North Pole.
But if you use no nagivational equipment other then starting out in a general direction, would you not hit the edge of the earth (in a plane)?
BTW how did your grandpa enjoy flying the Rapter? I think if I ever wanted to sign up for the armed forces I would want to go to College just to fly either a Raptor or the A-10 tank killer, the big ugly one if I got the name wrong :p
He absolutely loved it beyond belief. He still touts it as being the best all purpose jet ever created and that it shows the future of military aircraft. He was able to do several 90 degree landings on it as well and said it performed those better then the Harrier.
The A-10's are slowly being phased out in favor of high altitude aircraft that are capable of doing low yield cluster bomb attacks to get the same effect, as well as with drones. Ever since they outlawed all usage of incendiary ammunition against live personelle the A-10 has lost its main objective, which is crap because its a damned fine plane...