Specs: DARPA's space-age floater can travel nearly 2,000 miles a day and carry more than 500 tons. Not to be confused with a blimp or airship, the Walrus Aeroscraft generates 65 percent of its lift from helium and additional power from its body and propellers. A prototype is expected to hit the skies in 2009.

Military use: The Walrus operational vehicle will deploy payloads from non-traditional take-off sites on land and water-- runways need not apply.