Tens of millions of people say his name every year without knowing whose it is. They say it at a check-in desk, on a boarding pass, in a taxi line in Chicago: O’Hare. Behind the world’s busiest departures board is a 27-year-old fighter pilot who, on one February afternoon in 1942, flew alone into a formation of nine bombers to save an aircraft carrier — and a family story that runs straight through Al Capone’s Chicago.

His name was Edward Henry “Butch” O’Hare, and he became the US Navy’s first ace of the Second World War in about four minutes of flying.

Alone against nine

On 20 February 1942, the carrier USS Lexington was steaming near the Japanese stronghold of Rabaul when a wave of nine twin-engine “Betty” bombers came for it. O’Hare, a lieutenant in Fighting Squadron 3, launched to intercept — but his wingman, Marion Dufilho, found his guns jammed. That left one Grumman F4F Wildcat between the bombers and the ship.

O’Hare did not hesitate. He threw his fighter into the formation and attacked again and again, walking his fire from engine to engine, cockpit to cockpit, making every burst count. By the time other fighters arrived the attack was broken. He was credited with shooting down five bombers and damaging a sixth — an “ace in a day” in a single engagement. Later historians think the true figure may have been three, but the essential fact never changed: one pilot, alone, saved his carrier.

The student of Jimmy Thach

O’Hare did not become that deadly by accident. His squadron commander was John “Jimmy” Thach, one of the great tactical minds of naval aviation, and Thach drilled him relentlessly in gunnery and deflection shooting. When Thach dreamed up the defensive manoeuvre that would become famous as the “Thach Weave”, he chose O’Hare to help him test it in mock combat.

It worked so well that O’Hare could not get a clean shot at his own squadron mates. His report to Thach afterwards became one of the best-known lines in the story of the tactic.

A gangster’s son

The other half of the O’Hare story is almost stranger than the combat. Butch’s father, Edward “Easy Eddie” O’Hare, was a sharp Chicago lawyer who worked for Al Capone — and then quietly turned informant, feeding federal prosecutors the evidence that helped put Capone away for tax evasion. In November 1939, a week or so before Capone’s release from prison, Easy Eddie was shot dead at the wheel of his car.

Two and a half years later, his son stood in the White House. On 21 April 1942 President Franklin Roosevelt presented Butch O’Hare with the Medal of Honor — the first naval aviator to receive it in the war — and his wife Rita pinned it to his chest. A father who had run with gangsters; a son who became a national hero. It is hard to invent a cleaner arc of redemption.

The last flight

O’Hare kept flying and kept innovating. By late 1943 the Navy needed an answer to Japanese night torpedo attacks, and O’Hare helped pioneer the first carrier-borne night interception, a radar-guided “Bat Team” of Hellcats and a radar-equipped Avenger.

On the night of 26 November 1943, off the Gilbert Islands, he led that team into the dark in his F6F Hellcat. In the confusion of the first night carrier engagement he was shot down — whether by a Japanese gunner or, tragically, by friendly fire from one of his own team’s aircraft has never been settled. His body was never recovered. He was 29.

The name on the departures board

In 1949 Chicago renamed its new airport, then known as Orchard Field, in his honour: O’Hare International. Its airport code, ORD, is the last trace of that old orchard name. Today it is one of the busiest airports on the planet, and almost no one hurrying through it knows that the name belongs to a young man who once flew alone at nine bombers and won.

Sources: US Navy Medal of Honor citation; Naval History and Heritage Command; Congressional Medal of Honor Society; U.S. Naval Institute (“Butch’s Wingman”); HistoryNet.