A sign structure which may be supported from aircraft, and especially helicopters. The structure is comprised of three distinct sections which may be compactly transported and then easily assembled and connected around the landing gear on the underside of the aircraft. The structure provides an aerodynamically stable frame which may be supported in a direction transverse to the longitudinal axis of a helicopter. Novel electrically controlled light assemblies are attached in a rectangular matrix on the structure for displaying a desired illuminated message.
