It's the only unsolved hijacking case in the history of commercial aviation. On the afternoon of November 24, 1971—Thanksgiving Eve—a man aboard a flight from Portland to Seattle threatened to detonate a bomb if he didn't receive a hefty ransom. Once he got the money, the hijacker released all passengers and ordered the crew to fly to Mexico. En route, with cash in hand, the man parachuted from the aircraft.

This man was known as D.B. Cooper. After more than 50 years of FBI investigations, his identity, whereabouts and motive remain unconfirmed. No one even knows for certain whether he survived the jump. However, in 2023, the children of one of the prime suspects of the hijacking, reportedly shared evidence that could implicate their late father.

The FBI's extensive record on D.B. Cooper describes him as a "white male, 6'1" tall, 170-175 pounds, age-mid-forties, olive complexion, brown eyes, black hair, conventional cut, parted on left." Cooper boarded Northwest Orient Airlines Flight 305, he settled in his aisle seat at the rear of the 727, lit a cigarette, and ordered a bourbon and soda. Then he handed a note to Florence Schaffner, a 23-year-old flight attendant. "I have a bomb in my briefcase," it read. "I want you to sit next to me."

Schaffner did as instructed. Cooper told her the rest of his demands: $200,000 and four parachutes, delivered on landing at Sea-Tac Airport. While police and airline staff on the ground scrambled to assemble the money and chutes, the pilots flew in circles above Seattle. Passengers were told that a minor mechanical issue had forced the plane to burn fuel, prolonging a flight that would normally take 30 minutes.

After three-and-a-half hours in the air, the 727 finally landed. Having received his money and parachutes, Cooper dismissed all 36 passengers and two of the six crew members. The plane refueled and took off for Cooper's next requested destination: Mexico, via Reno and Yuma to refuel. During the first leg, with the crew in the cockpit, Cooper lowered the rear stairs and parachuted into a thunderstorm. He has never been found.

The FBI followed thousands of leads to find Cooper, considering more than 800 suspects in the five years following the incident. Below are some men who have been considered suspects.

On April 7, 1972, a man traveling under a fake name boarded a Newark-Los Angeles flight. Shortly after take-off, he handed a note to one of the flight attendants. The note demanded $500,000 and four parachutes. If these were not furnished, the man, a seasoned skydiver and helicopter pilot, would bomb the plane. The 727 landed and refueled, the hijacker exchanged passengers for cash and parachutes, and, en route to the next destination, he jumped from the rear stairs to freedom. Sound familiar?

This hijacking occurred less than five months after the D.B. Cooper incident, leading many to suspect that the same culprit may have been responsible. The perpetrator of the April crime, Richard McCoy, Jr., was convicted of air piracy and received a 45-year prison sentence. On August 10, 1974, however, he and some fellow inmates hijacked a garbage truck and escaped their Pennsylvania penitentiary. When the FBI finally tracked McCoy down in Virginia three months later, a shoot-out left him dead.

McCoy's children, Chanté and Richard III (Rick), have long believed their father might have been behind the 1971 hijacking. They finally opened up about their suspicions to Dan Gryder in 2023 after being repeatedly contacted by the amateur investigator. According to Gryder, they presented the FBI with a parachute and harness that had been stashed in a storage shed on their family's North Carolina property.

“That rig is literally one in a billion,” Gryder told Cowboy State Daily after posting a series on YouTube about his investigations.

Also stored with the parachute was a logbook that McCoy's daughter claims places their father at the site of the skyjacking. Chanté and Rick have said they waited until their mother passed away before sharing the items with investigators. The evidence could prove revelatory in a case that the FBI officially closed in 2016. Could it finally be enough to put the D.B. Cooper case to rest?

A more under-the-radar suspect through the years has been Sheridan Peterson, who fell under suspicion within a week of the skyjacking but wasn't interviewed by the FBI until decades later. Peterson, a former Boeing employee, worked in the department that wrote the flight manual for the Boeing 727 jet that was hijacked—a familiarity that might explain how the perpetrator knew the aircraft had back stairs he could open and jump from. An accomplished skydiver, Peterson worked for a time as a smokejumper in Montana. He also worked at the Issaquah Skydive Center in the early 1960s—the same place that would later provide parachutes used by Cooper in his escape.

Unlike descriptions of Cooper, however, Peterson has blue eyes, not brown. And while Cooper had chain-smoked on the flight, Peterson is not known to have been a smoker. At the time of the hijacking, Peterson told authorities, he was living with his wife and family in Nepal, although he offered no definitive proof that he hadn't traveled back at the time of the hijacking.

Back in the 1970s, pilot and former paratrooper Robert Rackstraw had a whole lot going on. Grand theft, $75,000 worth of bad checks, and the possible murder of his stepfather were just a few of the infractions for which authorities nabbed him. After being acquitted of the murder charge, Rackstraw saw fit to fake his own death in 1978 by logging a false mayday call from a rented plane in northern California. He spent two years in prison for check fraud and theft of an aircraft.

In the 2016 book The Last Master Outlaw, authors Thomas J. Colbert and Tom Szollosi presented evidence gathered during a five-year investigation into Rackstraw's past. They concluded he was the legendary hijacker, a claim Rackstraw's lawyer called "the stupidest thing I've ever heard." Rackstraw died from a heart condition on July 9, 2019.

Kenneth Christiansen had a more direct link to the Cooper incident: he had worked for Northwest—the hijacked airline—as a mechanic, flight attendant and purser. Kenneth's brother Lyle claims that when Kenneth was on his deathbed in 1994, he said, "There is something you should know, but I cannot tell you!"

Kenneth had been a military paratrooper. The year after the D.B. Cooper hijacking, despite being on a modest flight attendant's salary, he bought a house in cash.

Cannily, Cooper had taken his ransom note back from the flight attendant, so investigators were unable to examine it. Cooper did leave a few traces behind, though: some cigarette butts, a hair on the headrest of his seat and a clip-on necktie, which he tore from his collar before hurtling himself from the plane. Unfortunately, the FBI could not get any fingerprints from the items.

Though it was initially believed that Cooper was a battle-scarred skydiver—perhaps a paratrooper—further analysis found that he was likely no expert. "No experienced parachutist would have jumped in the pitch-black night, in the rain, with a 200-mile-an-hour wind in his face, wearing loafers and a trench coat," said FBI Special Agent Larry Carr in 2007. Investigators also thought Cooper acted alone. If he had worked with an accomplice, he would have requested a much more specific flight path rather than saying "Fly to Mexico" and jumping out when visibility was poor.

In 1980, a child's discovery reignited interest in the mystery. Eight-year-old Brian Ingram was digging in the sand on the banks of Washington's Columbia River when he found a bundle of rotting $20 bills totaling $5,800. When his parents contacted the police, they learned the serial numbers on the cash matched those from the stash given to D.B. Cooper. Aside from the few items left behind on the plane, this is the only material evidence found from the hijacking. Six years after he discovered the money, Ingram was allowed to keep $2,760 of it. In 2008 he sold 15 of the fragmented $20 bills at auction for $37,433.38.

In the wake of the hijacking, the Federal Aviation Administration ordered that "Cooper vanes," named after the elusive D.B., must be installed in all Boeing 727 aircraft. A Cooper vane is a small latch fitted to the outside of all planes with rear stairs. The latch prevents anyone from opening the door mid-flight, just as D.B. Cooper did as he leaped into the air—and vanished into obscurity.