Intended to be a heavy transport aircraft in the same category as the Lockheed C-5A, the CL-99 powered by four P&W JT3D-14 turbofans was proposed to the RCAF in 1961.

Unlike the studies for the CL-202 carried out in 1962, the CL-203 of the same year was a totally in-house design which would have been powered by two Rolls-Royce Spey engines.

One of several studies for a military tactical transport, the CL-202 was based on the Handley Page Herald.