Hydrogen Powered Quad, 4 Hrs Flight Time No Load, 2.5 Hrs 2.2 pounds load.

[lsnook]

http://www.roboticstrends.com/article/hycopter_drone_flies_for_4_hours_via_hydrogen_power

 

[ianwood]

Now that is interesting! I hope they make this work.

 

[Beario]

That should make for some really interesting long range flights

 

[Fyod]

Cool idea. Interested to see how complicated it'll be to have the tanks filled and if it'll be possible to swap them easily.
Ie. during the weekend you may not have a place nearby that would fill the tanks up.