The microwaves would be focused by the internal reflector to heat the air on one side or the other of the craft and push it in the opposite direction. Now the craft tilts from flying edgewise to flying flat into the air stream. That seems wrong but for another trick. The microwaves are reflected forward to create a superhot bubble of air above the craft and form an air spike that acts as the nose cone as the Lightcraft accelerates to 25 times the speed of sound. Even better, when the load is properly balanced the craft sails through the air without leaving a shock wave and virtually no supersonic wake.
Water is used by the craft to cool the rectennas and as a propellant in the last stages of ascent.
At least initially, during the prototype phase, it won't be for everyone, just NASA and military test pilots. In some Air Force Space Command schemes, the crew would breath an oxygenated fluid to protect their lungs. It all sounds a bit too much like science fiction, but Myrabo points out that most of the technologies or principles have been demonstrated. Faculty and students at Rensselaer have demonstrated the MHD slipstream accelerator and the air spike concept in a high-speed wind tunnel, and will test new models of other parts of the propulsion system later this year. At the Moon, the Lightcraft would zoom down a series of ring-shaped electromagnets that would slow the craft, or could accelerate another Lightcraft for the return to Earth.