Yeah, I got Power of Flight as well from GI. I think it's because the card art is the ad's art. Matches up, ya know.
But I have found 2 little booster packs (one a friend got from GDC for me and the other I got at Gamestop when I preordered the game), and those are random. Not a single duplicate either. Apparently, these packs of 10 are given out for various promotions that'll continue through April and into May; the packs even have an extra card that describes what they are with the name "Promotional Pack" so there ya go.