If you walked past an Apple storefront last year, you might have seen the display of the MacBook Air, appearing to float on the string of a balloon.

For the most valuable computer company in the world, the concept served as a witty, whimsical way to convey its ultra-light design. Yet there are several practical and extremely interesting applications of aerial computing that bleeding-edge researchers are pursuing.

The furor over the idea began earlier this week when the Pirate Bay, a Swedish website that enables file sharing, said it would launch a fleet of small flying servers.

Per its blog:

With the development of GPS controlled drones, far-reaching cheap radio equipment and tiny new computers like the Raspberry Pi, we’re going to experiment with sending out some small drones that will float some kilometers up in the air. This way our machines will have to be shut down with aeroplanes in order to shut down the system. A real act of war.

The Pirate Bay had its servers raided by police in 2006 and a multi-day outage of its service. Since then, it has pursued a number of measures to avoid another such outage — but this takes the game to new heights.

To be sure, flying computers aren’t new. Much of the cost of building a modern airplane goes to the avionics that control its local area network of controls. But the concept of sending machines up with the sole purpose of serving files (or unique resource identifiers) is very interesting. You can see an early example of just such a drone-driven aerial compute platform in the video embedded below.

The first aerial cloud service provider can’t be far behind. What you do with it? That’s your business. If nothing else, it provides another dimension to the concept of “uptime.”

Electronic Countermeasures @ GLOW Festival NL 2011 from liam young on Vimeo.