I never heard that song..
Without reciting lyrics, since that'd be crazy of me to ask, what's the song about?
(Mind you, I don't have volume/sound on my laptop, or yes, I'd listen for myself.)
So you can't hear the song? That sucks.
Anyway, it has two accepted meanings...
The first is Petty himself saying he got the song from a Pilots interview and how he described landing a plane was the hardest part of the whole flight, the other being about drugs and the habit.
However, for me personally going with what I THOUGHT the song was about when I first heard it, is maturing and learning to deal with life and what it brings. "Landing is the hardest thing" and for me represents what I consider are the daily struggles I deal with, while flying, or learning to as it is, is the representation of me trying to find peace in the world and learn to smile and laugh despite those struggles.
Or something like that.

I am terrible at describing sensations I feel.