A year or two ago, I found an app for my iPhone that tracks air traffic radar from airports around the world. It's called Flightradar24, and now it's a version for Mac. What this clear app does is nothing short of remarkable. You see pictures of planes moving in and out of airports near real time. But that's not all. It also shows comprehensive data on each aircraft;
Flightradar24 lets you search for a particular aircraft, filter flights with airlines, speed, location, altitude and see both flights and call signs right on your Mac screen.
Look at the details presented on the Mac screen.
What about aviation coverage?
Flightradar24 covers the entire US and Canada, but with a 5-minute delay (radar data comes from the FAA). The coverage is significant in most developed countries, but limited in Africa. Almost 95 percent of Europe is covered.
Zoom out from a region and you'll see almost all air traffic.
Zoom in or out on the map area, click on a plane and see the details. It's so simple.
Personally, I found the iPhone and iPad versions to work better, and you can use the app to see a facsimile of the horizon from the cockpit perspective. Every now and then, a particular aircraft disappears from the view or cannot be found just to return later. It is probably caused by incomplete data. Real-time coverage is limited to aircraft equipped with ADS-B transponders.