On May 8, 1927, French pilots Charles Nungesser and François Coli took off from Paris in a biplane named L'Oiseau Blanc, or the White Bird. The World War I veterans were aiming to become the first aviators to make a nonstop transatlantic flight to New York, but after last being spotted over Ireland, their plane vanished without a trace. Just two weeks later, Charles Lindbergh successfully crossed the Atlantic in a monoplane called the Spirit of St. Louis. He would go on to worldwide fame, but the fate of the men who nearly beat him to the honor remains a mystery to this day.

On the night of May 21, 1927, aviator Charles Lindbergh touched down at France’s Le Bourget Field, having completed history’s first nonstop flight between New York and Paris. Upon exiting the Spirit of St. Louis, the 25-year-old American was mobbed by a crowd of 150,000 people who hoisted him on their shoulders in celebration. He spent the next several days as the toast of Paris, yet for many French citizens, his triumph was bittersweet. Just two weeks before Lindbergh conquered the Atlantic, a pair of French pilots named Charles Nungesser and François Coli had vanished while trying to accomplish the same feat in the opposite direction. They had yet to be officially declared dead, but with each passing day, their chances of survival were dwindling. The delicateness of the situation was not lost on Lindbergh, who arranged a visit with Nungesser’s mother shortly after arriving in Paris. “You are a very brave young man,” she told him during the meeting. “I, too, have a brave son, who I have never ceased to believe is still fighting his way back to civilization.”

Charles Lindbergh’s 3,600-mile flight vaulted him to international fame, but it’s often forgotten that he was only one of more than a dozen pilots and navigators who were competing for the same honor. The great air race had kicked off in 1919, when a French-American hotel mogul named Raymond Orteig offered a $25,000 reward to the first aviator to make a nonstop flight between New York and Paris. British pilots John Alcock and Arthur Brown made a nonstop transatlantic flight from Newfoundland to Ireland that same year, but Orteig’s bounty remained unclaimed until the mid-1920s, when several different teams stepped up to the challenge.

<img src="http://cdn.history.com/sites/2/2017/05/Carte_postale-Oiseau_blanc-1927-E.jpeg" alt="Post card of the White Bird, a French biplane which disappeared in 1927, during an attempt to make the first non-stop transatlantic flight between Paris and New York. The aircraft was flown by French aviation World War I heroes Charles Nungesser and Francois Coli. (Credit: Carte postale)” width=”686″ height=”385″ class=”size-E wp-image-191264″ /> Post card of the White Bird, a French biplane which disappeared in 1927, during an attempt to make the first non-stop transatlantic flight between Paris and New York. The aircraft was flown by French aviation World War I heroes Charles Nungesser and Francois Coli. (Credit: Carte postale)

The major competitors for the Orteig Prize were a veritable who’s who of early aviation. They included René Fonck, a celebrated fighter pilot who had been the Allies’ “aces of aces” during World War I, and Richard E. Byrd, an American who had won the Medal of Honor for flying a plane over the North Pole. Perhaps the most flamboyant contenders were Charles Nungesser and François Coli, a pair of Frenchmen who planned to make the crossing in a two-seater Levasseur PL.8 named L’Oiseau Blanc, or the White Bird. Nungesser had lived a swashbuckling life that included stints as a gaucho in Argentina and a Hollywood stunt pilot. Coli, meanwhile, had achieved several endurance flying records over the Mediterranean. Both men had also served as French fighter pilots during World War I, and they had the scars to prove it. Coli wore an eyepatch as a result of a crash that had left him partially blind, and Nungesser had survived 17 war wounds and endured so many surgeries that the New York Times described him as “part platinum.”

Unlike most of the Orteig Prize challengers, the French duo planned to begin their crossing in Paris and end in New York. With Nungesser serving as pilot and Coli as navigator, they would fly their open cockpit biplane over England, Ireland and the Atlantic before buzzing Newfoundland and Nova Scotia. They would then finish in grand style by making a water landing in New York near the Statue of Liberty or Battery Park. The white-painted L’Oiseau Blanc had been modified to carry over 1,000 gallons of fuel—enough for over 40 hours in the air—and it was outfitted with a watertight bottom and detachable landing gear that would allow the pilots to cut down on weight. As a good luck charm, Nungesser had the plane emblazoned with his World War I flying emblem: a black heart with a skull and crossbones.

Charles Nungesser and Francois Coli standing in front of 'L'Oiseau Blanc' in France. (Credit: Central Press/Getty Images)
Charles Nungesser and Francois Coli standing in front of ‘L’Oiseau Blanc’ in France. (Credit: Central Press/Getty Images)

Early on May 8, 1927, Nungesser and Coli climbed into the cockpit of L’Oiseau Blanc at Paris’s Le Bourget Field. The threat of foul weather in the Atlantic had deterred Lindbergh and some of the other Orteig competitors from taking off so early in the month, but the French daredevils were willing to gamble in the hope of winning the race. Nungesser got a last-minute injection of caffeine to ensure he was perked up for takeoff, and Coli received a tearful goodbye kiss from his wife. At 5:17 a.m., as a sea of spectators looked on, L’Oiseau Blanc chugged down the runway and took to the sky. “The crowd stood spellbound, hats in hands, as the beautiful machine disappeared into the mists of early day,” the New York Times wrote.

After jettisoning their landing gear, Nungesser and Coli sped west to the French coast and crossed the English Channel. They were last sighted over southern Ireland around 10:30 a.m., at which point they flew off into the vast expanse of the Atlantic Ocean. L’Oiseau Blanc was not outfitted with a radio, so for the next day, the world could only wait in anticipation for it to reappear over North America. By the afternoon of May 9, thousands of people had gathered in Manhattan to wait for the plane to make its triumphant landing. When the appointed time came and went with no sign of Nungesser and Coli, search planes were dispatched to scout for them along the American coast. Back in France, one newspaper jumped the gun and published an evening edition that read “THE ATLANTIC IS CONQUERED,” but it wasn’t long before telegraph messages confirmed the gloomy reality: L’Oiseau Blanc was missing in action.

Charles Nungesser and his Levasseur plane 'L'Oiseau blanc.' (Credit: Albert Harlingue/Roger Viollet/Getty Images)
Charles Nungesser and his Levasseur plane ‘L’Oiseau blanc.’ (Credit: Albert Harlingue/Roger Viollet/Getty Images)

Over the next several days, Nungesser and Coli became the subject of an international rescue operation. Ships and aircraft from the United States, Canada and France scoured the North American coastline in search of a sign that the plane had ditched in the sea. Floyd Bennett, an American Orteig Prize competitor who had been injured when his plane crashed on takeoff, even came out of the hospital to lead an airborne search. Yet by the time Charles Lindbergh finally made his transatlantic crossing in late May, there was still no sign of the French pilots. In his autobiography, Lindbergh would later write that Nungesser and Coli had simply vanished “like midnight ghosts.”

In the ninety years since its final flight, the fate of L’Oiseau Blanc has remained one of the most tantalizing mysteries in aviation. It’s possible that the flimsy aircraft was forced down in the Atlantic and lost in a storm, but many modern researchers maintain that Nungesser and Coli successfully crossed the ocean and reached the North American coast. Several witnesses in Maine and Newfoundland claimed to have either seen or heard the plane buzz overhead in May 1927, and a few reported hearing it crash. That same year, reports surfaced of white-colored airplane wreckage being recovered off New York. Among the many theories still in circulation is that Nungesser and Coli were knocked off their intended route by a squall before running out of fuel and crash landing somewhere along the East Coast. It has even been suggested that the fliers were mistakenly shot down by Prohibition-era rumrunners or U.S. Coast Guard forces.

The theory that L’Oiseau Blanc conquered the Atlantic is certainly provocative, since it would mean that Nungesser and Coli successfully flew between mainland Europe and North America before Charles Lindbergh. The full extent of their journey may never be known for sure, but even in the 1920s, their attempt was hailed as a remarkable example of heroism in the name of technological progress. One notable monument to the pilots was erected in 1928 at Paris’s Le Bourget Field—the spot were Lindbergh finished his flight and where Nungesser and Coli began theirs. “In honor of those who tried,” reads its inscription, “and of the one who succeeded.”