Models on lines and flying in circles predate manned flight. Early versions merely constrained the model to fly in a circle but offered no control. This is known as Round-the-pole flying. The origins of control-line flight are obscure but the first person to use a recognizably modern system is generally considered to be Oba St. Clair, in June 1936, near Gresham, Oregon.St. Clair's system used a rather large apparatus similar to a television antenna, onto which many lines were attached. This system is very different from those currently in use on modern control line models.
The name most associated with the promotion of control line, and the inventor of the formerly patented system known as "U-Control" (which was a trademark, and is the system in use on virtually every two-line control line model today) was Nevilles E. " Jim" Walker. His "American Junior" company was by far the biggest producer of models, and held numerous patents on the two-line system until overturned during a patent infringement suit, by Walker, against Leroy M Cox, based on "prior art" from St. Clair in the 1955 trial. One of the most coveted prizes in control-line aerobatics competition sanctioned by the AMA, awarded to the winner of a flyoff between the US Junior, Senior, and Open age class Champions, was originally provided by and is named for Walker. This is one of the oldest perpetual trophies in modeling that is still awarded.