Having a huge line of sight doesn't solve the problem. The receiver has to be oriented roughly perpendicular to the incoming beam in order to get any reasonable efficiency. And the receiver has to be large in order to account for beam dispersion and aiming inaccuracy. For aerodynamic reasons the receiver can only be on the top or bottom of the aircraft and can't be angled much. So therefore the power transmitter must be close to directly above or below the aircraft.

Battery energy density is steadily improving every year. The 2019 Nobel Prize in Chemistry went to the inventors of the lithium ion battery.

https://www.nobelprize.org/prizes/chemistry/2019/press-relea...