Was the plane crash earlier today really a terrorist attack?

Terrorism, at it's core, is meant to spread fear and panic throughout a society to undermine it. I've read the guy's note and yeah he really bashes the government, but it seems more like crazy rambling than a political manifesto. I mean at least Islamic terrorists are against us because of our foreign policy has been screwing them over for a few decades. This guy was just plane nuts who happened to own a plane. I mean are we going to start labeling every person who starts shooting up a post office a terrorist now? Don't you think we're kind of overreacting a bit?