One of the main attractions at the 2011 Paris Air Show was the Solar Impulse, a prototype aircraft powered exclusively by sunlight. It's only a single seater and is regularly delayed by either too much wind or too little sun, but it is a remarkable aircraft, solar powered and able to fly during day or night. And luckily for onlookers, conditions at the Paris show on Sunday were perfect for the Solar Impulse's first public demonstration flight. The aircraft flew for 20 minutes in front of large crowds at Bourget airport, where the world's aviation industry is gathered for the biennial Paris Air Show. The Solar Impulse is powered by the sun through 10-thousand solar cells which cover its 63-metre (207-feet) wingspan and generate about 40 horsepower, about the same power a small scooter uses, according to the flight team. Show Less >>