I'm imagining very big hot air balloons can maybe lift up the batteries, the batteries would actually be on an unmanned drone that can fly fast to follow the passenger airplane to dock to it, when the battery is swapped, that drone would fly back with the depleted battery to attach itself to that balloon again. The very big baloo system would also carry solar panels to charge the battery again and to keep the balloon battery drone system up indefinetely (creating more hot air as needed and doing all the automatic controls and getting commands for when to unleash the battery pack unmanned airplane from ground).
My guess is the battery pack and docking drone systems with solar panels would be so heavy it requires maybe a too large a balloon to keep in the air indefinitely and docking with an unmanned drone is maybe not that easy. May not be very practical for the passenger airplane to slow down every 2 hours to do maneuvers to dock with the drone to swap the battery.
Before I read the story earlier today on about Chip Yates Long-ESA transatlantic electric flight planned for 2014, I never considered that docked battery swapping for electric airplanes was a possibility.
I'm a big fan of Project Better Place for electric cars, which standard is all about all electric cars needing to have swappable batteries so the electric car battery range is not a problem, and also so people who buy electric cars don't need to buy the battery but instead lease/rent it from the renewable electric energy supplier who also owns all the batteries and ads newer better batteries to the system as those become available.
Last edited by Charbax; 10th May 2013 at 11:57.