I'm a bit of an airliner freak, so I love looking up at the contrails of jets flying overhead and wondering where a plane might be going. I recently found out that Wolfram Alpha has the ability to tell you what airplanes are cruising around above you based on your position and its knowledge of where various airline and charter flights are located at any point in time. Since Siri has the built-in ability to work with Wolfram Alpha, I thought I'd see if I could just ask Siri to tell me about those flights overhead.
It took a few tries and some thought about what to ask Siri, but I finally got it to work. Telling Siri to "Ask Wolfram what flights are overhead" produces the correct results. That query displays a Wolfram Alpha printout showing the flight or aircraft registration number of flights that are currently visible from where you're standing, their altitude, and the angle above the horizon. You also get information on what type of aircraft each is, how far away it is, and what direction to look, as well as a sky map showing where the planes are.