> we no longer need one huge engine and lots of passenger to get good efficiency Larger ships and planes are more efficient than smaller ones. Longer trains ar

> we no longer need one huge engine and lots of passenger to get good efficiency Larger ships and planes are more efficient than smaller ones. Longer trains are more efficient than shorter ones. No matter how efficient your propulsion is, it’s always more efficient when installed in bigger vehicles. Unless we figure out free energy, I don’t think we should stop at any arbitrary “good efficiency”.