Here’s what you’ll learn when you read this story:

• L-8 was a Goodyear advertising blimp repurposed by the Navy to hunt enemy submarines during WWII, and on a late summer morning in 1942, it took off with two crewmen aboard.
• Many eyewitnesses spotted the blimp patrolling the Bay Area, but when it crash-landed in a suburb several hours later, there was no sign of either of its crewmen.
• Rumors and conspiracy theories sprang up around the disappearance, but what exactly happened to the crew of L-8 remains unknown.

It was almost noon on August 6, 1942, when Ethel Appleton of Daly City, a suburb on the edge of San Francisco, held her daughter in terror after she heard a mysterious scraping sound coming from her roof. Her neighbor, Richard L. Johnston, had been waxing his car when he eyed what appeared to be a monstrous shadow above Bellevue Avenue. He immediately dropped his polishing rag and ran to shield his mother. It was not a moment too soon, because sparks erupted from the electrical wires of a nearby utility pole when a U.S. Navy blimp crashed head-on into it.

The blimp, a repurposed Goodyear vessel called L-8, had strayed from its course, appearing as if out of nowhere in a residential neighborhood. At the time, the U.S. had only been involved in World War II for nine months, and Japanese forces had already sunk half a dozen Allied ships off the California coast and shelled a massive oil drilling facility. L-8’s mission over the Pacific Ocean was to track and destroy Axis submarines, so the repurposed Goodyear blimp was armed with two 365-pound depth bombs and a .30-caliber machine gun with 300 rounds of ammunition. Its crew, veteran Navy airmen Lieutenant Ernest Cody and Ensign Charles Adams, were experienced fliers. Cody had even flown L-8 before in an effort to deliver cargo to a warship before a Tokyo raid.

That slightly overcast morning, Cody and Adams took off in L-8 from Treasure Island and headed out to patrol the area around the Farallon Islands, Point Reyes and Montara before their return. L-8 (also called Love-8) had been aloft for an hour and a half when Cody spotted a suspicious dark smudge beneath the surface of the ocean. He radioed about an “oil slick,” code for a possible enemy submarine, at 7:42 a.m. and dropped smoke flares into the ocean before investigating further.

While sailors aboard the nearby U.S. Liberty ship SS Albert Gallatin and the fishing boat Daisy Gray noticed Allied aircraft, there was nothing about the regular coastal blimp patrol that struck them as unusual. But, peering through their binoculars at the L-8 and its crew, they were unaware that was the last time anyone would see Cody and Adams alive.

The blimp floated past witnesses without issue until Richard Quam, an off-duty seaman, noticed its deflating form on his way to the beach. He grabbed his camera, and his impromptu photo would later be taken in as evidence. L-8 finally touched down on Bellevue Avenue after scraping across the roofs of several houses, including Appleton’s, and hitting Johnston’s car. The door had been latched open, the loudspeaker system’s microphone was dangling out the open door, and the engine was still running, but there was no sign of Cody or Adams. Authorities were able to determine only that the blimp had dumped some of its fuel to increase buoyancy fast. Search and rescue teams scoured the area for one of its missing depth bombs, which was found on a golf course, but there was still no sign of the men. They had officially gone missing.

Rumors about the missing crew of the “ghost blimp” haunted the Bay Area. Because they were required to wear life jackets while flying the blimp, it was no surprise that Adams and Cody’s life jackets were missing from the aircraft. However, all three of the gondola’s parachutes and its life raft were still aboard the L-8.

Some speculated that the men had gone AWOL, or that the flares were actually used to show where one crewman had fallen instead of marking the oil slick sighting. Perhaps the other crewman jumped out in an attempt to rescue the former but didn’t survive the fall, though nobody among the many eyewitnesses of the blimp’s flight had seen anyone falling.

Others thought they might have been captured by the Japanese, but there was no evidence of any bombing or of the other damage that would have been almost inevitable in that scenario. Some wilder theories suggested that both crewmen had been involved in a love triangle, with one murdering the other before taking his own life. And of course, some have suggested an alien abduction as the source of the disappearance.

Decades later, researcher Otto Gross thought he had finally found an answer. After starting his own investigation on L-8 in 2009, he claimed that he’d been able to access documents from the Department of Defense that proved the blimp was being used to test new radar equipment, and the crewmen had possibly gone unconscious from an onslaught of microwaves. However, there was no hard proof of these claims, and the website where Gross posted these unconfirmed assertions is now defunct.

Two days after the incident, the Navy held a formal investigation, calling 35 witnesses over seven days, yet the inquiry ended with—still—no answers. After a year with no sign of either Cody or Adams, the men were declared dead.

The blimp itself was returned to Goodyear after the war, and it flew over many football and baseball fields under the new name America until it was retired in 1982. It now sits on display at the National Naval Aviation Museum, the gondola repainted with its old L-8 design and markings, still at the center of a mystery that, in all likelihood, will never be solved.