AIRCRAFT, BLEED-AIR SYSTEMS FOR AIRCRAFT, AND METHODS OF PROVIDING THRUST TO AIRCRAFT

Bleed-air systems comprise a bleed-air turbine configured to receive at least a first portion of bleed air from a jet engine and deliver it to a cabin, a cabin-exhaust compressor operatively coupled to the bleed-air turbine and configured to receive cabin exhaust air from the cabin, and a cabin-exhaust nozzle configured to receive the cabin exhaust air from the cabin-exhaust compressor. Aircraft comprise a fuselage, a wing, a jet engine, and a bleed-air system. Methods comprise expanding at least a first portion of bleed air from a jet engine to drive a cabin-exhaust compressor, compressing cabin exhaust air from a cabin with the cabin-exhaust compressor, and nozzling the cabin exhaust air to environment.