JK, not a feature, just chuck testa! 
. Apaprently an iPhone caught fire on a flight. My iPhone 4S hardly even gets hot and my wife (on the iPhone 4) said hers doesn't get "more than warm" usually (just texted her). Does anyone else ever see their phone get fiery hot? Going to investigate with my close friends to see if there is a real danger. 
http://www.bgr.com/2011/11/28/apple-iphone-spontaneously-combusts-aboard-flight-in-australia/
http://www.bgr.com/2011/11/28/apple-iphone-spontaneously-combusts-aboard-flight-in-australia/