Probably mostly by not expending energy to climb and then descend. Helicopter lift efficiency varies heavily with altitude, but how it varies depends on the we

Probably mostly by not expending energy to climb and then descend. Helicopter lift efficiency varies heavily with altitude, but how it varies depends on the weight of the helicopter. Heavy helicopters require quadratically more torque to hover at higher altitudes, but lightly-loaded helicopters can actually require less torque to hover at higher altitudes. Here's a (complicated but really cool) diagram to calculate on page 7, figure 7-6. https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/helicopter_flying_handbook/media/hfh_ch07.pdf https://www.faa.gov/regulations_policies/handbooks_manuals/a... Since electric motor current draw is approximately linearly proportional to their torque, heavy-lift electric helicopters/drones would almost certainly conserve energy by flying lower. I'm not sure how that applies to this drone, which probably weighs below the lowest line on that diagram, and also has more, smaller, higher-speed rotors. This vehicle probably spend most time traveling as a fixed-wing aircraft, and for those, efficiency almost always increases with altitude. (Except that their combustion-powered engines may require compressors to continue operating at higher altitudes. This aircraft's ICE may actually suffer from this, if it is an inexpensive engine not designed for aircraft.) So if the statement is correct, it's probably referring to the energy saved by not having to climb in the first place.