In the quest to extend the flight time of the AR.Drone David Homan has fitted a Zippy 2200mAh battery to his AR.Drone. This will take your flight time to roughly 30 minutes according to David. In his blog post David explains that you need to take the extra weight into consideration while landing. He advises to bring the drone further down manually before hitting the landing button. He has some pictures in his blog post that show how he has attached the battery (which has a different form factor and weight) to his AR.Drone.