The M22 Locust was designed to fulfill the need for an airborne light tank following the rapid expansion of the US's parachute forces shortly before its entry into World War II. The British were also involved in the project, having requested such a tank to be carried by glider. The M22 had a welded hull and cast turret, and was armed with a 37-mm M6 gun. However, armor protection was poor, being vulnerable even against armor-piercing .50-in rounds. Its greatest deficiency, however, was in its airlift capability. In US service, it was designed to be carried under a C-54, but this required the removal of the turret which delayed its readiness on the battlefield. In British service, it was able to be fitted on a Hamilcar glider, however, yet it saw combat only briefly during the crossing of the Rhine in February 1945 with the 6th Airborne Division. US and British units were retired after the war but some were supplied to the Egyptian Army.

Various proposals were offered for the US Army's airborne light tank design, of which the Marmon-Herrington prototype, the Light Tank T9 was accepted. Numerous structural improvements (including brackets so it could be slung under a C-54) resulted in the T9E1 which was later renamed M22. No other variants were produced.