A system for controlling an operating mode of an airship , comprising: a sensor system configured to determine an altitude of a bottom of a hull of the airship , the hull configured to be inflated with a lighter-than-air gas; and a computer processor configured to execute logic instructions to: determine the altitude of the airship based on information from the sensor system; determine an operating mode of the airship ; determine whether to increase, decrease or maintain the altitude and airspeed of the airship based on the operating mode; and generate signals to open or close a valve and operate a ballonet fan to control gas pressure within the hull and a ballonet enclosed in the hull of the airship based on a desired airspeed, altitude, and operating mode, characterised in that the valve is coupled between a plenum chamber of an air cushion landing system (ACLS) and the ballonet , the plenum chamber is formed by a landing surface and the ACLS when the ACLS is in contact with the landing surface , the generated signals controlling the valve to selectively allow air to flow from the plenum chamber into the ballonet while the ACLS is in contact with the landing surface , the generated signals further controlling the ballonet fan to draw air into the ballonet . a sensor system configured to determine an altitude of a bottom of a hull of the airship , the hull configured to be inflated with a lighter-than-air gas; and a computer processor configured to execute logic instructions to: determine the altitude of the airship based on information from the sensor system; determine an operating mode of the airship ; determine whether to increase, decrease or maintain the altitude and airspeed of the airship based on the operating mode; and generate signals to open or close a valve and operate a ballonet fan to control gas pressure within the hull and a ballonet enclosed in the hull of the airship based on a desired airspeed, altitude, and operating mode, characterised in that the valve is coupled between a plenum chamber of an air cushion landing system (ACLS) and the ballonet , the plenum chamber is formed by a landing surface and the ACLS when the ACLS is in contact with the landing surface , the generated signals controlling the valve to selectively allow air to flow from the plenum chamber into the ballonet while the ACLS is in contact with the landing surface , the generated signals further controlling the ballonet fan to draw air into the ballonet . determine the altitude of the airship based on information from the sensor system; determine an operating mode of the airship ; determine whether to increase, decrease or maintain the altitude and airspeed of the airship based on the operating mode; and generate signals to open or close a valve and operate a ballonet fan to control gas pressure within the hull and a ballonet enclosed in the hull of the airship based on a desired airspeed, altitude, and operating mode, characterised in that the valve is coupled between a plenum chamber of an air cushion landing system (ACLS) and the ballonet , the plenum chamber is formed by a landing surface and the ACLS when the ACLS is in contact with the landing surface , the generated signals controlling the valve to selectively allow air to flow from the plenum chamber into the ballonet while the ACLS is in contact with the landing surface , the generated signals further controlling the ballonet fan to draw air into the ballonet . <EOS>