http://www.chron.com/disp/story.mpl/...y/6141635.html

But fuel cells have perennially remained a year or two away from reaching the market as companies have worked on making them small, cheap and long-lasting while making sure they don’t overheat.
The U.S. government removed a key roadblock this year when the Department of Transportation amended its hazardous materials regulations to allow cells with methanol, butane or formic acid to be carried on airplanes. Methanol and butane are flammable, and formic acid is corrosive.
“That was one of the largest challenges to this market, to overcome that regulation issue,” said Sara Bradford, an energy and power systems consultant for Frost & Sullivan