A propulsion system includes two gas turbine engines and an air-provisioning system. The air-provisioning system includes a first ejector, a second ejector, a plenum fluidically connected with the first ejector and the second ejector, and a first propulsor. The air-provisioning system is configured to bleed and mix air from each gas turbine engine in the ejectors so as to provide selectively a flow of plenum air from the plenum to the first propulsor at a desired pressure and a desired flow rate to power the first propulsor.