Would it make sense to jettison the discharged batteries shortly after takeoff to reduce cruising weight? The "takeoff battery pack" could be in some sort of autonomous drone that pilots itself back to the airport so it could be jettisoned after reaching cruising altitude.
Does weight make a significant difference once the aircraft is at cruising altitude?
Yes, planes for ages jettisoned any fuel before landing because of the weight. Keeping the landing weight down to a minimum does wonders for the airframe design.
Nowadays they just do a better job of loading only the fuel necessary, and circle pointlessly to burn excess fuel before landing. It's still an issue, they just don't dump the fuel on the neighborhood below like they used to.
I was thinking more about helping with the energy density issue, by discarding the discharged, yet just as heavy as when charged, batteries after reaching the energy intensive climb to cruising altitude.
Does weight make a significant difference once the aircraft is at cruising altitude?