In the late 1960s, the whole country had its head in the clouds. The sky wasn’t the limit anymore. Supersonic planes were going to take us, in the words of John F. Kennedy, “to all corners of the globe” and then straight into the future — after all, you can’t spell The Jetsons without jet. The Boeing supersonic transport (SST), commissioned by the U.S. government on December 31, 1966, was to lead the way. The American answer to the Anglo-French Concorde, the SST would have been the quickest thing on two wings. Early sketches described a plane traveling at such speeds that “passengers are almost unaware they are flying.”

But comfort for those in midair meant disquiet for those on the ground. Supersonic planes create super-loud sonic booms. When an aircraft breaks the sound barrier, it pushes the air in front of it away so forcefully that a high-pressure shock wave is created. If this shock wave passes over you, you hear a loud “boom”—just as we hear thunder after lightning causes sudden air-pressure changes. Because an SST outpaces sound for its entire journey, it creates not just one thunderclap, but a whole “boom carpet” that unfurls continuously behind it. One transcontinental Boeing SST flight would have left about five million headaches in its wake.

When William Shurcliff pictured an SST cutting through the clouds, he imagined not the great swell of progress, but this startling aftermath. Shurcliff—an accomplished physicist, with forty papers and a dozen patents under his belt—considered himself “a very shy fellow.” He spent his time canoeing and playing tennis when he wasn’t in his office at the MIT-Harvard Cambridge Electron Accelerator. But Shurcliff had also been a technical aide on the Manhattan Project and knew firsthand what happens when people fail to anticipate the unintended consequences of scientific progress.

Spurred by this wariness, and by the “whitewashed,” “sugar coated” science (as he put it) found in reports commissioned by the Federal Aviation Administration, Shurcliff started writing letters. He wrote to the authors of the FAA reports, expressing his fear of the end of “a golden era in the US…. when a man’s home was a place where he could live quietly.” He wrote to the Civil Aeronautics Board (“I take my sleep seriously”), to dozens of Congressmen, and to citizens who shared his concerns. From March 1966 to ’67, he wrote about five pounds of letters. Increasingly, Shurcliff asked whether his correspondents knew of any national groups that aimed to “attack the sonic boom threat vigorously.”

“I want to give a lot of money to such a group,” he explained—money, and more of his time, and the information he had amassed from sheaves of studies, reports, and correspondence.

It became clear that the man for the job was right behind Shurcliff’s nose. In late February 1967, his “fairly intense one-man campaign against the SST” went public and became The Citizen’s League Against the Sonic Boom (CLASB for short). Thus was born one of the more successful grassroots environmental movements in U.S. history.

CLASB meetings were held in the Shurcliff residence, at 19 Appleton Street in Cambridge; the first, in March 1967, drew thirteen members, all correspondents and colleagues of Shurcliff’s. By their second meeting, the group had opened a checking account to deal with donations; by their fourth, they were hiring secretaries. For everything they took in, they put out twice as much—CLASB produced newsletters, fact sheets, “sonic-boom bang-zone maps,” letters to various editors, and an eighty-page SST handbook. Members appeared on radio and television, and Shurcliff testified in front of President Nixon’s ad hoc SST committee.

Even as he expanded his efforts, Shurcliff stuck to his strengths—speed, thoroughness, and follow-through, sweetened by a “personal touch.” Take, for example, CLASB’s 1969 campaign to win over the boating public. Someone brought up yachtsmen in a May meeting; by June, CLASB had mailed specially formulated anti-SST letters and petition cards to all 800 members of the Cruising Club of America, warning that their beloved coastal waters could soon become “a vast dumping-ground for sonic booms.” As of July 10, they had gathered over 100 yachtsmen’s signatures and a week later drafted a letter to President Nixon, as well as a press release. CLASB ran similar campaigns to attract conservation organizations, anti-noise groups, and mink farmers, among others.

Despite predictions in the original CLASB proposal, Shurcliff never found “somebody else to take on the main load,” and CLASB never left its “temporary” office at 19 Appleton Street. But when Congress voted to defund the Boeing SST in 1971—a vote spurred partially by, in the words of Time magazine, “a sizable citizens’ army of environmentalists”—over five thousand CLASB members let out a quiet, respectful whoop.