I. The Prohibition

Section 91.817 of Title 14 of the Code of Federal Regulations is titled, with unusual directness, “Civil aircraft sonic boom.” Subsection (a) provides: “No person may operate a civil aircraft in the United States at a true flight Mach number greater than 1 except in compliance with conditions and limitations in an authorization to exceed Mach 1 issued to the operator in accordance with § 91.818.”¹ The prohibition is categorical. The exception is a single piece of paper.

The ban dates to 1973, when the Federal Aviation Administration prohibited civilian supersonic flight over land with Regulation 91.817, the rule that still stands today.² The agency did not act on theory. In 1964 it conducted a six-month test over Oklahoma City, subjecting the population to 1,253 intentional sonic booms to gauge the public’s attitude toward supersonic flight.³ The public’s attitude turned out to be measurable in claims: Americans had already filed roughly 40,000 of them against the Air Force over boom damage and disruption in the 1950s and 1960s.⁴ Congress canceled the American supersonic transport program in 1971, the FAA issued the ban two years later, and the Concorde, which flew commercially from 1976 to 2003, was restricted to supersonic speeds over water on its American routes for its entire service life.⁵ Twenty Concordes were built; fourteen saw passenger service.⁶ Not one of them was ever permitted to boom over Oklahoma City.

The regulation has now stood for fifty-three years. In those fifty-three years, the operator this investigation concerns has never once complied with it.

II. The Operator

The operator is thunder, and the Federal Government’s own scientists have already classified its product. The National Oceanic and Atmospheric Administration states, in its official lightning science materials: “Thunder is the acoustic shock wave resulting from the extreme heat generated by a lightning flash.”⁷ Lightning, the agency reports, “can be as hot as 54,000°F (30,000°C), a temperature that is five times hotter than the surface of the Sun.” When lightning occurs, it heats the air surrounding its channel to that temperature in a fraction of a second, producing what the agency calls “explosive expansion”: the air “expands so rapidly that it compresses the air in front of it, forming a shock wave similar to a sonic boom.”⁸

The agency’s educational materials go further. In its lesson on determining the distance to a thunderstorm, NOAA explains that as the lightning bolt passes through the air, “the air expands faster than the speed of sound, generating a ‘sonic boom.’” Because the boom is created along the entire path of the bolt, “in effect, millions of sonic booms are created, which we hear as a rumble.”⁹

A careful reader will note that the regulation governs Mach numbers, which describe the speed of an object through air, while thunder is air itself moving. This investigation notes it too, and proceeds anyway, on the authority of the government’s own vocabulary. When the National Oceanic and Atmospheric Administration says a phenomenon generates a sonic boom, this publication takes the agency at its word. The word “sonic” is doing the work. The boom is doing the rest.

III. The Scale of the Violation

The National Weather Service reports an average of twenty to twenty-five million cloud-to-ground lightning strikes in the United States every year.¹⁰ Every strike produces its shock wave. By the agency’s own accounting, each flash generates its boom along the full length of the channel, meaning the annual national output of unauthorized sonic-boom events numbers in the billions, conservatively counted.

Against this, consider the compliance record of the law-abiding. On March 24, 2023, Boom Supersonic petitioned the Federal Aviation Administration for a special flight authorization to exceed Mach 1 for flight testing of its XB-1 experimental aircraft. The agency granted the authorization on April 7, 2024: up to twenty supersonic test flights over one year, confined to the R-2508 airspace complex over Edwards Air Force Base, at or above 30,000 feet mean sea level.¹¹ Thirteen months of administrative process, an environmental assessment published in the Federal Register, and a defined test range, for twenty flights.

The ratio of authorized supersonic operations to unauthorized ones, in the United States, in any given year, is approximately twenty to several billion. The authorized twenty fly at 30,000 feet over a desert test range. The unauthorized billions detonate at altitudes from the cloud base to the ground, over cities, suburbs, farmland, and schools, at all hours, in all seasons, with no environmental assessment, no defined range, and no authorization of any kind.

IV. The Missing Application

Section 91.818 prescribes exactly what a special flight authorization requires. The application must be made to the FAA Office of Environment and Energy, and it must include: (1) the name of the operator; (2) the number and model or models of the aircraft to be operated; (3) the number of proposed flights; (4) the date range during which the flights would be conducted; and (5) the time of day the flights would be conducted.¹¹ The regulation adds, with the particular bureaucratic tenderness reserved for the small hours: “Proposed night operations may require further justification for their necessity.”

The operator has never supplied any of it. It has no name on file with the Office of Environment and Energy. It operates no numbered models. Its proposed number of flights is approximately twenty-five million per year, its date range is “in perpetuity,” and its time of day is “whenever the atmosphere feels like it,” none of which has ever been committed to an application because no application has ever been filed.

The application form assumes, at every line, an applicant that can write. The operator cannot write. It cannot name itself, list its models, or justify its night operations, further or otherwise. The regulatory scheme’s completeness is its vulnerability: a process designed to scrutinize every boom has no procedure for a boomer that cannot hold a pen.

V. The Night Operations

The regulation singles out night operations for special scrutiny. The Administrator may demand further justification before permitting supersonic flight after dark, a provision aimed at protecting the sleeping public from exactly the kind of startling, window-rattling detonation that thunder performs as a matter of routine.

Thunder booms at 2 AM. It booms at 3 AM. The summer squall line that rolls across a county at midnight conducts unbriefed night supersonic operations over populated areas, the precise scenario the application process was written to examine, and it does so having offered no justification at all, let alone the further kind.

The residents woken by the 3 AM crack are experiencing what the regulation’s drafters feared most: a supersonic event over a sleeping population with no authorization on file. The drafters imagined an aircraft. They did not imagine that the sky itself would be the repeat offender, which is why the night-operations clause has never once been enforced against its most prolific violator.

VI. The Noise Record

The historical record is unambiguous about what booms do to people. Oklahoma City endured 1,253 of them in six months, and the nation rewrote its aviation law. The Air Force collected 40,000 claims. The Concorde was confined to the oceans. The entire architecture of American supersonic regulation rests on a single premise: that sonic booms over land are intolerable, and that anyone who wishes to produce one must first convince the Administrator.

The operator has never been convinced of anything, and its booms are unmuffled. While NASA’s Quesst program has spent decades methodically working through the challenge of quieting the boom, culminating in the X-59 experimental aircraft, which completed its first supersonic flight on June 5, 2026, and reached Mach 1.4 at 55,030 feet a week later, the operator’s product remains at full volume.¹²¹³ The X-59 exists to prove that a boom can be shaped into a mere thump, so that the 1973 ban can finally be reconsidered. Thunder has never shaped anything. Its thump is the thing the X-59 was built to avoid being.

In the summer of 2026, the Federal Aviation Administration published a Notice of Proposed Rulemaking that would replace the speed-based prohibition with a noise-based standard: supersonic flight would be permitted if the sonic boom overpressure at the surface does not exceed 0.11 pounds per square foot.¹³¹⁴ The proposal is precise, quantitative, and enforceable. It requires measurement, modeling, and a finding by the Administrator. The operator’s overpressure at the surface has never been measured, never been modeled, and never been submitted for any finding. There is no measurement program. There is no model. There is only the boom, which exceeds every standard ever proposed by the margin by which weather exceeds paperwork.

VII. The Definitional Void

Section 91.817 governs “civil aircraft,” and thunder is not a civil aircraft, and this investigation discloses the fact plainly, as the genre requires. The regulation was written for machines with pilots, flight manuals, type certificates, and maximum operating limit speeds. The operator has none of these. It has no Mach meter, because it is not flying; it has no flight manual, because there is no flight; it has no pilot, because there is no cockpit.

There is also the question of whom to serve. The authorization process demands the name of the operator, and the operator’s name is not on file anywhere in the Federal Aviation Administration, because the operator has never introduced itself. It cannot be served with process. It cannot be deposed. It cannot be ordered to show cause, because there is no address at which cause could be shown, unless the agency is prepared to serve a summons on a cumulonimbus cloud, which it is not, although the cloud would deserve it.

The regulation’s completeness is, once again, its undoing. Every line assumes an applicant. The one entity that produces more sonic booms than every applicant in history combined is the one entity the application process cannot describe, which is why the process has never touched it.

VIII. The Enforcement Impossibility

The Federal Aviation Administration possesses formidable tools. It can ground an aircraft. It can suspend a certificate. It can assess civil penalties under 49 U.S.C. § 46301. Against the operator, every tool misfires. There is no aircraft to ground, because the operator was never aloft in the regulatory sense. There is no certificate to suspend, because none was ever issued. There is no person against whom to assess a penalty, because the operator is not a person, and the statute’s per-violation arithmetic, applied to billions of annual boom events, would produce a figure with no one to pay it and no account from which to collect.

The agency could issue an emergency order of prohibition. There is no one to issue it to. It could demand the filing that Section 91.818 requires. The filing would have to list, as the number of proposed flights, a number in the tens of millions, as the date range, forever, and as the time of day, all of them. The Office of Environment and Energy has no form for forever.

The ban has stood for fifty-three years. In that time the operator has conducted well over a billion unauthorized supersonic events over the United States, by the conservative arithmetic of this investigation.¹⁵ It has never applied for authorization. It has never been granted authorization. It has never been penalized, never been grounded, never been quieted, and never once justified its night operations, further or otherwise. The Concorde obeyed the oceans. Boom Supersonic obeyed the process. The X-59 obeys the future noise standard before it is even final. The operator obeys nothing, and booms on.

Ergo.