There are moments when technology still makes our jaws drop. This is one of them.
We'll let iPhone app Plane Finder AR's App Store description speak for itself: "Point the camera at a plane and you'll see the flight number, aircraft registration, speed, altitude and how far away it is!"
It's based on an existing service called Plane Finder, which tracks planes using something called ADS-B - the signals transmitted by commercial airliners with all this data.
There's already a Plane Finder app that uses maps, but Plane Finder AR adds augmented reality into the mix. That's the camera-pointing bit.
Okay, so the social currency in being able to tell friends 'That plane's going to Paris, y'know' may have a limited shelf-life. Still, the fact that this is even possible is deeply cool.