Low-boom supersonic aircraft

In plain language

A supersonic aircraft flies faster than the speed of sound, which is roughly Mach 1. As it does so, it creates shock waves, and these reach the ground as a sonic boom, a loud bang heard along the flight path. Designers shape aircraft so that the pressure changes are weaker and spread out, which can make the boom quieter. The aim is a quieter boom, not silence.

Two recent developments are easy to confuse. NASA's X-59 research aircraft flew faster than sound in June 2026, but the chase aircraft's booms drowned out any sound from the X-59, so that flight did not show what people on the ground would hear. Boom Supersonic's smaller XB-1 demonstrator also flew supersonically in 2025. Neither aircraft carries passengers, and the rules for supersonic flight over land are still only proposed.

Technical explanation

Sonic booms are a pressure signature at the ground, not a single sound at the moment the aircraft passes Mach 1. The proposed FAA rule measures surface overpressure. The FAA's July 2026 proposed rule, as summarised by DLA Piper, sets a limit of 0.11 pounds per square foot (psf) at the surface. The sound profile of a real aircraft over real communities, in varying weather, is what the proposal's acceptance depends on, and the sources reviewed do not yet give that profile for any passenger design.

The propulsion side is separate from the boom. Boom's Symphony engine has a high-pressure core, the high-pressure spool of the engine. Boom's reported work so far is component testing: a June 2024 announcement of combustor rig tests on a one-eighth section of the combustor module, and a November 2025 series of single-nozzle flame tests with Georgia Tech. Boom planned a sprint core engine test in 2026. The sources reviewed do not report full-engine testing or certification of Symphony.

The regulatory sequence matters for timing. The FAA's proposal would allow overland supersonic flight under a noise-based standard, but it is not a final rule. The FAA also plans a separate Part 36 rule for take-off and landing noise. No date for that rule appears in the sources reviewed, and the FAA does not expect type-certificate applications for supersonic aircraft until after it.

What the evidence says

Each statement is typed by the strength of its evidence and linked to the source that supports it.

Limitations and open problems

• X-59 is a research aircraft. It carries no passengers, so its flights do not show airline capacity, range, operating cost, airport compatibility or emissions.
• The first supersonic flight did not show ground-level sound, because the chase aircraft's sonic booms obscured any sound made by the X-59.
• The FAA overland rule is a proposal. Overland service would also depend on a final rule, aircraft certification, and acceptance by other countries' regulators.
• XB-1 is a small demonstrator. Symphony testing reported so far covers combustor and nozzle components; no full-engine test or certification is reported in the sources reviewed, and no published result from the planned 2026 core test was found when checked on 21 October 2026.
• Overture's passenger count and cruise speed are company figures, not measured service performance. Boom's product page lists 130 orders and pre-orders, which do not by themselves guarantee delivery or scheduled service.
• Take-off and landing noise near airports, fuel burn, climate effects beyond carbon dioxide, and airline economics are not addressed by the sources reviewed.

Possible future uses

Timeline

1. 27 Jun 2024Boom announces Symphony combustor rig testing, using a one-eighth section of the combustor module at Florida Turbine Technologies' facility in Jupiter, Florida. Sources: [4]
2. 10 Feb 2025XB-1 completes its 13th test flight, the last flight in the company's flight table, which reports a maximum Mach number of 1.18. Sources: [3]
3. 28 Oct 2025NASA's X-59 research aircraft makes its first flight. Sources: [1]
4. 19 Nov 2025Boom and Georgia Tech report single-nozzle combustor flame tests and plan a sprint core engine test in 2026. Sources: [5]
5. 5 Jun 2026The X-59 exceeds Mach 1 for the first time, reaching about Mach 1.1 at 43,400 feet, according to NASA. Sources: [1]
6. 2 Jul 2026The FAA proposed rule 'Enabling Supersonic Overland Flight' is published in the Federal Register. Sources: [2]

Futures this could help bring about

How far away?

Supersonic passenger flights returning

Engineering prototypes · 2 of 8 steps done

Glossary

Mach number

The ratio of an object's speed to the speed of sound in the surrounding air. Mach 1 is the speed of sound.

Sonic boom

A pressure wave heard on the ground as a loud bang when an aircraft flies faster than sound.

Overpressure

The pressure above normal air pressure created by a shock wave. The FAA proposal limits it at ground level, measured in pounds per square foot (psf).

Low-boom design

Aircraft shaping intended to weaken or spread shock waves so that the sonic boom at ground level is quieter.

Sources

1. government report
   NASA's X-59 Aircraft Flies Supersonic for First Time
   NASA, Jun 2026. Accessed 21 Oct 2026.
2. other
   Proposed FAA rule would allow civil supersonic flight over the United States
   DLA Piper, 6 Jul 2026. Accessed 21 Oct 2026.
3. company announcement
   XB-1
   Boom Supersonic, 2025. Accessed 21 Oct 2026.
4. company announcement
   Symphony Enters Rig Testing
   Boom Supersonic, 27 Jun 2024. Accessed 21 Oct 2026.
5. company announcement
   A Small Flame with Big Implications: Testing Symphony's Combustion System
   Boom Supersonic, 19 Nov 2025. Accessed 21 Oct 2026.
6. company announcement
   Overture
   Boom Supersonic, 2026. Accessed 21 Oct 2026.

Revision history

3 changes since this profile was created.