Pratt & Whitney ceased production of the Wasp Junior in 1953, having built 39,037 engines.[3] Many Wasp Junior engines are still in use today in older bush planes and agricultural planes, as well as in antique aircraft. Some antique aircraft, such as the Boeing-Stearman Model 75, which originally used other engines, have had them replaced with the Wasp Junior to provide more power or for easier maintenance, since parts for the Wasp Junior are readily available.