'Fun'.
What's 'fun' about it?
This isn't rhetorical. I want someone to explain to me how flight is fun. What is so fascinating about moving in three dimensions? Do you enjoy swimming, too?
Explain.
Edit: Don't give me that freedom bullshit, either. Avoiding the entirety of the game world and calling it 'freedom' is laughable. What are you free to do? Be lazy?