The Lockheed P2 "Neptune" was originally designed for submarine searching, using magnetic detection gear or acoustic buoys. Besides flying maritime reconnaissance, the aircraft served as an experimental night attack craft in the attempt to interdict the movement of enemy truck convoys. Another model, the OP2E, dropped electronic sensors to detect truck movements along the supply route through Laos known as the "Ho Chi Minh Trail".

The Ho Chi Minh Trail was used by the North Vietnamese for transporting weapons, supplies and troops. Hundreds of American pilots were shot down trying to stop this communist traffic to South Vietnam. Fortunately, search and rescue teams in Vietnam were extremely successful and the recovery rate was high.

Still there were nearly 600 who were not rescued. Many of them went down along the Ho Chi Minh Trail and the passes through the border mountains between Laos and Vietnam. Many were alive on the ground and in radio contact with search and rescue and other planes; some were known to have been captured. Hanoi's communist allies in Laos, the Pathet Lao, publicly spoke of American prisoners they held, but when peace agreements were negotiated, Laos was not included, and not a single American was released that had been held in Laos.

The Neptune had precise navigational equipment and accurate optical bombsight. Radar was housed in a well on the nose underside of the aircraft, and radar technicians felt especially vulnerable working in this glass bubble nosed aircraft. The aircraft could place seismic or acoustic devices within a few yards of the desired point. To do so, however, the OP2E had to fly low and level, making it an easy target for the enemy's anti-aircraft guns that were increasing in number along the Trail.

On February 17, 1968, an OP2E from Observation Squadron 67 departed Thailand in a flight of four aircraft on an operational mission over Laos. The crew of the aircraft included Commander Glenn M. Hayden; Lt.Jg. James S. Kravitz;
Lt. Curtis F. Thurman; Ensign James C. Wonn; AO2 Clayborn W. Ashby, Jr.; ADJ2 Chester L. Coons; AN Frank A. Dawson; ATN1 Paul N. Donato; and AN James E. Martin.

After completion of the first target run, the aircraft reported to its fighter escort and forward air control aircraft that it had been hit by small arms fire but would continue with the second target run.
 
During the second run, the fighter escort reported the starboard engine of the OP2 on fire. The OP acknowledged the report and aborted the rest of their mission to return to home base. The last radio transmission from the aircraft was, "we're beat up pretty bad."

The fighter escort climbed to the top of the overcast to await the OP2 rendezvous, but the aircraft never emerged from the cloud base. The fighter dropped below the clouds to search for the OP2 and found burning wreckage.
No parachutes were seen, nor were any emergency radio beepers heard. Search and rescue efforts were negative. Investigation of the crash site was not feasible because of enemy presence in the area. The aircraft crashed about
34 kilometers northwest of Xepone in Savannakhet Province, Laos. The crash site was situated 2,800 meters south of Route 91 in rugged terrain on the side of a 550 meter ridge, approximately 4 kilometers northwest of Muang
Phin. The aircraft was on a reconnaissance mission and carried no ordnance. Because there was no direct witness to the crash of the OP2, it is not known whether any of the crew of nine survived, but it was assumed that they did
not. All nine aboard were classified Killed, Body Not Recovered. Although this aircraft went down in a relatively populous area, it is not known whether the enemy knows the fates of the crewmembers.