Though there are no limits to the designers' fantasy or creativity in building their craft, there are still a few rules to obey. Firstly, the 'planes' should be manually-operated only – no motors, engines or fuel allowed. Secondly, all machines must fit within width and weight limits.

As hundreds look on, the jury judges the flights according to these criteria: speed, originality and showmanship. These are also among the key aims of the inventors who have the chance to set new records.

The longest flight was set in 2000 in Austria where a man-powered aircraft made 195 feet (almost 60 metres).

The first Red Bull Flugtag was held in Vienna, Austria, in 1991. Since then more than 35 Flugtag festivals have been staged worldwide – from Ireland to the U.S. west coast.

The competitions attract more and more people every year, winning admiration from growing numbers of spectators. And professional and amateur engineers of all ages take up the challenge to try and pedal (or flap) their way to victory.