Method of deploying from a folded, transport condition to a launch condition a mobile aircraft launcher. A launch beam comprises a plurality of beam sections hinged to one another, the beam sections being generally side-by-side in the folded, transport condition, and collinear to define a continuous rectilinear beam in the launch condition. An aircraft-engaging shuttle is mounted on the launch beam for movement along the length of the launch beam. The method comprises supporting the launch beam in a horizontal attitude; pivoting the beam sections relative to one another from their generally side-by-side positions to their collinear position while the launch beam is supported in the horizontal attitude; moving the launch beam to an inclined position for launch; and supporting the launch beam in the inclined position during launch.