General James Doolittle of the United States Army Air Forces (USAAF), hero of the daring “Doolittle Raid” on mainland Japan and later the unified commander of Allied air forces in Europe in World War II, offered the following high praise to one of his staff officers in 1944: “Next to a letter from home, Captain Miller, your organization is the greatest morale builder in the European Theater of Operations.” The Captain Miller in question was the trombonist and bandleader Glenn Miller, the biggest star on the American pop-music scene in the years immediately preceding World War II and a man who set aside his brilliant career right at its peak in 1942 to serve his country as leader of the USAAF dance band. It was in that capacity that Captain Glenn Miller boarded a single-engine aircraft at an airfield outside of London on December 15, 1944—an aircraft that would go missing over the English Channel en route to France for a congratulatory performance for American troops that had recently helped to liberate Paris.

It would be difficult to overstate the magnitude of Glenn Miller’s success in the years immediately proceeding America’s entry into World War II. Though he was a relatively unspectacular instrumentalist himself—he’d played the trombone in various prominent orchestras but never distinguished himself as a performer—Miller the bandleader came to dominate the latter portion of the swing era on the strength of his disciplined arrangements and an innovation in orchestration that put the high-pitched clarinet on the melody line doubled by the saxophone section an octave below. This trademark sound helped the Glenn Miller Orchestra earn an unprecedented string of popular hits from 1939 to 1942, including the iconic versions of numbers like “In The Mood” (1939), “Tuxedo Junction” (1939) and “Chattanooga Choo Choo” (1941), as well as Miller’s self-penned signature tune, “Moonlight Serenade” (1939).

The Glenn Miller Orchestra played its last-ever concert under Miller’s direction on September 27, 1942, in Passaic, New Jersey, and shortly thereafter, Miller entered the Army. After nearly two years spent stateside broadcasting a weekly radio program called I Sustain The Wings out of New York City, Miller formed a new 50-piece USAAF dance band and departed for England in the summer of 1944, giving hundreds of performances to Allied troops over the next six months before embarking on his fateful trip to France on this day in 1944.

The wreckage of Miller’s plane was never found. His official military status remains Missing in Action.