The F/A-18C is the single-seat variant and the F/A-18D is the two-seat variant. The D-model can be configured for training or as an all-weather strike craft. The "missionized" D model's rear seat is configured for a Marine Corps Naval Flight Officer who functions as a Weapons and Sensors Officer to assist in operating the weapons systems. The F/A-18D is primarily operated by the U.S. Marine Corps in the night attack and FAC(A) (Forward Air Controller (Airborne)) roles.
The F/A-18C and D models are the result of a block upgrade in 1987 incorporating upgraded radar, avionics, and the capacity to carry new missiles such as the AIM-120 AMRAAM air-to-air missile and AGM-65 Maverick and AGM-84 Harpoon air-to-surface missiles. Other upgrades include the Martin-Baker NACES (Navy Aircrew Common Ejection Seat), and a self-protection jammer. A synthetic aperture ground mapping radar enables the pilot to locate targets in poor visibility conditions. C and D models delivered since 1989 also have improved night attack abilities, consisting of the Hughes AN/AAR-50 thermal navigation pod, the Loral AN/AAS-38 NITE Hawk FLIR (forward looking infrared array) targeting pod, night vision goggles, and two full-color (formerly monochrome) multi-function display (MFDs) and a color moving map.