This CD process is more efficient than allowing a convergent nozzle to expand supersonically externally. This differs from detonation, which propagates supersonically through shock waves, decomposing a substance extremely quickly. As flight speed increases supersonically the shock system is initially external. Its sonic boom made travelling supersonically over land impossible without causing complaints from citizens. This is not ideal for ballistics, especially supersonically where a higher fineness ratio is desirable. It could also cruise supersonically without afterburner, as demonstrated on a delivery flight.