I thought I would share this as I us it before and while flying to check for helicopters. The app is free, tracks all air traffic on a map and gives the altitude. When i fly i have it on a separate device and it helps a ton.
Flightradar24.com - Live flight tracker!
Flightradar24 Free on the App Store
Flightradar24 Free - Android Apps on Google Play
Flightradar24.com - Live flight tracker!
Flightradar24 Free on the App Store
Flightradar24 Free - Android Apps on Google Play