The Lockheed P-2 Neptune (originally designated P2V until September 1962) was a Maritime patrol and ASW aircraft. It was developed for the United States Navy by Lockheed to replace the Lockheed PV-1 Ventura and PV-2 Harpoon, and being replaced in turn with the Lockheed P-3 Orion. Designed as a land-based aircraft, the Neptune never made a carrier landing, although a small number of aircraft were converted for carrier use and successfully launched. The type was successful in export and saw service with several armed forces.
During the Vietnam War, the Neptune was used by the US Navy as a gunship, an overland reconnaissance and sensor deployment aircraft, and in its traditional role as a maritime patrol aircraft. The Neptune was also utilized by the U.S. Army's 1st Radio Research Company (Aviation), call sign "Crazy Cat," located at Cam Ranh Bay, as an electronic "ferret" aircraft. Observation Squadron 67 (VO-67), call sign "Lindy", was the only P-2 Neptune aircraft squadron to ever receive the Presidential Unit Citation. VO-67 lost three aircraft and 20 aircrew due to ground fire during its ultra secret missions into Laos and Vietnam in 1967–68.
The ROCAF/Taiwan's secret 34th Squadron's RB-69A/P2V-7U ELINT/SIGINT aircraft flew a low level electronic reconnaissance from Da Nang, flying over Thanh Hoa province on 20 August 1963 to investigate a air resupply drop zone that turned out to be a set trap for a ROCAF C-123B airdrop mission 10 days earlier due to the air inserted agents were captured and turned. Next year an air defense radar mapping mission was also flew by 34th Squadron's RB-69A/P2V-7U aircraft into North Vietnam and Laos on the night of 16 March 1964. The RB-69A took off from Da Nang, flew up the Gulf of Tonkin before coasting in near Haiphong, then flew down North Vietnam and the Laos border. The mission was requested by SOG for helping plan the insert or resupply of agents. Seven AAA sites, 14 early warning radar sites and two CGI radar signals were detected.