This is the only solely ion propelled series of aircrafts that can lift their power supplies against earth’s gravity. These prototypes were patented specifically for lifting their onboard power supplies and the widely published patent has been in effect since 2014.

While the craft wasn’t working at full power for this test footage since their was a power loss, the safety tether still went completely loose when the craft was energized, and it is also shown flying outdoors. There is an indoor flight that lasted for almost 2 minutes continually when it was flying at its best. There is a video of that and other sustained flights on this YouTube channel.

Previously all heavier than air ion propelled aircrafts had to be connected through thin wires to large heavy power supplies that remained fixed to the ground.

This series of prototypes have been independently verified to fly with onboard power since 2006. It was necessary to increase the EAD thrust to weight ratio by several orders of magnitude as well as other upgrades to get it operational.

Here is a link to a broadcast about the craft with the host of NPR Jeff Saint Clair. His article and radio program certifies fist hand, that this ion propelled aircraft US Patent number 10119, 527, lifts its power supply:

https://radio.wosu.org/post/exploradio-oberlin-inventor-pushes-limits-ion-powered-flight#stream/0