In reply to The Lemming:
I don't suppose we'll be seeing solar powered passenger/freight transport systems. I do suspect we'll see unmanned solar powered, high altitude communication/surveillance aircraft deployed within the decade.
I suspect solar-battery technology will be adopted quite early into self-launching and self-sustaining sailplanes. Power systems are the main focus of commercial competition/development in the sailplane market at the moment and battery-electric power is already on the cusp being performance/price competitive with IC.
The Solar Impulse circumnavigation is an impressive demonstration of renewable energy technology, human ingenuity and the courage/determination it takes to claim these big adventure records.
jk