Just a small addendum: the Sears-Haack body is the shape with the least amount of wave drag under supersonic regime, but its derivation (using the Prandtl-Glaue

Just a small addendum: the Sears-Haack body is the shape with the least amount of wave drag under supersonic regime, but its derivation (using the Prandtl-Glauert equation) is not valid for transonic flow, where the best approach so far seems to be maintaining the cross sectional area constant. So if we optimize for supersonic flight it won't be so good for transonic and vice-versa... I agree with you in that probably there's no way to passively eliminate sonic booms, maybe some kind of "active" solutions, but the weight problem strikes again. Also, I don't know if a rocket can be made without boom, as the transition in the nozzle is abrupt. Maybe it's time to review those aerospikes!