A system for providing compressed air to pneumatic loads in a vehicle such as an aircraft, the system includes a gas turbine engine having; a) an engine compressor with an air inlet coupled to an interior of a cabin of the vehicle; and b) a load compressor coupled to the gas turbine engine having a compressed air outlet coupled to one or more pneumatic loads of the vehicle. One or more electrically driven cabin air compressors (CAC) have compressed air outlets coupled to the one or more pneumatic loads.