The Grumman E-1 Tracer was notable for being the first operational carrier-based airborne early warning (AEW) system. It was based on the S-2 ASW aircraft and was originally taken as merely a variant of the Tracker and was in fact known as the "Stoof with a Roof" according to its counterpart's nickname. The reason was obvious: the E-1 featured a prominent airfoil shaped dome that protected a massive parabolic dish antennae for the APS-82 radar (which also required a twin tail in place of the S-2's single fin). The radar featured an Airborne Moving Target Indicator (AMTI) which could distinguish an aircraft in flight from wave clutter on the ocean surface. Tracers began to be deployed on US Navy carriers at the end of the 1950s replacing the aging Guardians and Skyraiders which performed similar duties. They were phased out in favor of the newer E-2 in 1976.

Based on the S2F (as the Tracker was then known), the first WF-1 had its maiden flight on 17 December 1956 and was later ordered into production as the WF-2. After 1962, both versions became known as the E-1A (WF-1) and E-1B (-2).