I've had that app for quite awhile. I'm a commercial airline enthusiast, especially the heavy jets. Get a few in Houston but not like you get in the major population centers.
When I see a heavy over head at about 36,000 ft, I whip out the Flight Radar and try and figure out what it is.
Usually, it's just AF Cargo flying to Mexico City.
Boring !!!
As it stands, I love the following:
www.airliners.net
SpeedbirdHD on Youtube:
http://www.youtube.com/user/SpeedbirdHD
www.flightaware.net (can track planes coming to and from any airport...I love KJFK !!
and more.