Well, anyone with a little bit of sense, the internet, and about 10 minutes to do the research can find out how long the flights take. When you add up the numbers, you'll notice that something is incredibly off. Unless, of course, you're part of the vast majority who believes in a round Earth.
The problem here is that people justify their zealous beliefs to ridiculous lengths, trying to satisfy themselves. Admitting you're wrong is very difficult, especially when you build your life around a concept. I'm a born again atheist as of six months ago, and I'll be twenty-seven in a month. I was literally crying, scared at my realization. But when I got over it, I started to study the theories behind the big bang, evolution, abiogenesis, etc... And I found them fascinating, and even comforting.
Admitting when you're wrong is difficult, but it comes with a certain sort of bliss.