Flying is pretty exhausting - so much to do, such a lot to think about. It does get easier the longer you fly, as you get used to it and it becomes more natural. In my albeit limited experience, it never becomes as easy as driving, but that could be because I drive nearly every day, but few of us fly that often. So we're always rusty to a certain extent, and usually stretched in a way we're not when we're driving.
That's how I see it, anyway.