A long haul jet is at takeoff roughly evenly split by weight between fuel, passengers, and plane. Yes, it becomes lighter, but the more importantly it scavenge

A long haul jet is at takeoff roughly evenly split by weight between fuel, passengers, and plane. Yes, it becomes lighter, but the more importantly it scavenges it’s entire takeoff weight in oxygen which conventional lithium ion batteries can’t do. Lithium batteries have improved, but you have to carry both sides of the redox. The only way I can think to get similar physics is to use lithium air batteries and then dump them with a parachute when discharged.