You're laying on a grassy knoll, staring at clouds, thinking about puppies and wondering if Becky and/or Brian Jones will go with you to the school dance. Then a plane flies overhead. You wonder where it'll end up. But you no longer have to wonder: Wolfram Alpha will tell you.
It's an awesome -- and supremely nerdy -- new feature that the computational search engine has cooked up: it will poll your geoIP location and tell you what planes are overhead. And that the mobile apps take advantage of the feature actually makes it somewhat usable IRL.
If you run a search for "planes overhead", it will return a list of any and all planes your eyeballs can spot, the flight number, where they're positioned in the sky and how high up they are. In the browser version, the flight version is hyperlinked, showing you its flight path. Sadly, in the mobile version, you have to manually search the flight number. And it may take some of the fun out of your whimsical ruminations, but whatever. Knowledge is power. [Wolfram Alpha via Cnet]