A wheeled transporter is used for air cargo. It comprises a load-carrying platform having rollers, connected at one edge to a power console incorporating a prime mover, and supported at the other edge with unpowered castoring wheels. Two steerable wheels located beneath the console adjacent opposite ends drive the transporter. Each steerable wheel is driven by a reversible motor, and is steerable so that when one wheel is turned in one direction the other is turned in an opposite direction. The transporter can thus be driven in either direction along path (X), and turned or rotated on (Z). By turning the wheels through 90 degrees to the longitudinal direction, the transporter can be driven along a path (Y) in either direction, and steered by varying the differential speed of the wheels.