I'm pretty positive this came from Gmail.

It also regularly updates me when my flights status changes (delays, gates changed, that sort of thing).

I'm really torn on this. Part of me says "hey, I never [expressly] said you could look at that" and another part is saying "that's really neat".

This is all a YMMV situation... I find that if I google something associated with a physical address on my desktop machine, logged into google, my phone will have a card with directions to that location.

That can be useful, but it's usually just an annoyance as I only wanted to call them or do something on their website.

Anybody have a solution to deactivate that behaviour?

They don't make a secret of the fact that they scan your gmail account for a lot of Google Now's functionality.

I believe it scans your gmail for things like flights and package deliveries.