Supersonic 2.0: How Three Visionary Startups Are Reviving Faster Air Travel

The space between the first commercial supersonic flight in 1969 and the current era of slow, safe airplanes spans 56 years—yet airlines have made only incremental gains in speed while adding safety and environmental safeguards. The fastest commercial jet still in service, the Boeing 747‑8, cruises at 0.85 Mach, half the speed of Concorde and nowhere near the 1.7 Mach envelope once promised to shrink trans‑Atlantic trips from seven hours to three and a half. Three pioneering companies—Boom Supersonic, Astro Mechanica, and Hermeus—are pushing the boundaries of supersonic flight and laying out a commercial roadmap. Their progress illustrates that the barriers of noise, cost, and regulation are lower than they have appeared for decades. ## Boom Supersonic: Quiet, Efficient Mach‑1.7 Trains In 2023 Boom’s XB‑1 flew a private, one‑engine test platform that broke the sound barrier without producing a ground‑heard sonic boom. By flying at the optimal altitude and applying AI‑driven atmospheric modeling, the jet’s Mach cutoff trajectory bent the sonic wave upward, satisfying the U.S. Federal Aviation Administration’s 1974 ban on audible sonic booms over land. The quiet technology won the first regulatory green‑light for over‑land supersonic flight in the United States. Boom’s next‑generation airframe, Overture, will carry 80‑100 seats on a sleek needle‑nose design and is targeted at business‑class customers who currently buy premium seats on subsonic jets for up to $20,000. The core of Overture’s performance is its Symphony engine—a four‑spool, non‑afterburning turbofan built in-house from nickel alloy. At 14,000 lb, each engine is heavier than the entire test aircraft, yet its variable‑ratio fan and compressor stages allow it to operate efficiently at Mach 1.7, a regime where traditional engines either stall or produce prohibitively high fuel burn. Because the Symphony engine improves specific thrust and reduces fuel consumption, Boom estimates a round‑trip trans‑Atlantic ticket at $5,000—roughly the cost of a typical business‑class cabin on a subsonic jet. Boom already has 130 placed orders from U.S. carriers such as United and American, and the company foresees a fleet life‑cycle cost advantage that could reshape long‑haul economics. The timeline is ambitious: Overture’s first test flight is slated for 2030, with FAA certification expected by 2033. The company’s approach to regulatory engagement—leveraging the recent executive order that allows non‑booming supersonic flights—optimizes the path to market without sacrificing safety or environmental performance. ## Astro Mechanica: Adaptive Hybrid Engines and an Uber‑style Business Model Astro Mechanica, founded by pilot‑turned‑engineer Ian Brooke, is challenging the industry’s reliance on static turbofan architectures. The company’s turbo‑electric adaptive engine blends electric fan, turbofan, ram‑jet, and rocket‑like modes into one modular system. At low speeds, the engine behaves like an efficient turbofan, minimizing drag and fuel consumption during take‑off and landing. In the supersonic regime it transitions smoothly into a ram‑jet, taking advantage of compressive heating to sustain Mach 1.5‑2.0 without auxiliary combustion. Three generational prototypes—Gen 1 (electric compression), Gen 2 (subsonic validation), & Gen 3 (dual‑mode integration)—have already flown hot‑fire tests, with each iteration completing in less than a year. What sets Astro apart is its aggressive focus on fuel economy; the company is optimizing engines from the ground up to run on liquified natural gas (LNG), which burns 30 % less CO₂, offers 60 % more range, and is ten times cheaper than kerosene. Astro’s commercial vision is Uber‑for‑supersonics: on‑demand point‑to‑point flights that bypass major hubs, reduce ground times, and eliminate empty‑payload cruising. The business begins with defense contracts—hypersonic (Mach 5) capabilities are attractive to the U.S. Department of Defense for rapid strategic mobility. Demonstrating reliability in military context will generate cash and validate high‑performance technology before scaling to civil markets. ## Hermeus: The Hypersonic Leap to Mach 5 Hermeus, led by AJ Piplica, focuses on the far‑right side of the speed spectrum: sub‑space, Mach 5 flight that would shrink New York–London to 90 minutes. Confronting the classic supersonic dilemma—engines that can take off on a runway but cannot sustain high speeds—the company built a hybrid Chimera engine: a turbojet that accelerates the aircraft to Mach 3 before retracting its turbine and deploying a ram‑jet that pushes into Mach 5 within five seconds. Hermeus follows a quarterly development cycle—dubbed the Quarterhorse program—to accelerate risk reduction. Mk 1, the first year‑long prototype, flew in 2023; Mk 2 is expected to reach supersonic speeds in early 2026. Later prototypes will test the turbine-to-ram‑jet transition and evaluate the precooler technology needed to keep turbine temperatures within safe limits while the airframe approaches Mach 5. Defense revenue is the company’s launchpad; the U.S. armed forces are willing to pay a premium for strategic advantage. Success in the Pentagon’s demanding test environments will unlock the commercial market with a proven, reusable, and cost‑efficient high‑speed airframe. ## Where Supersonic 2.0 Will Hit the Ground All three startups share a common thesis: advance the engine to break previous performance limits, prove the technology under stringent defense contracts, then leverage that success to serve civilian markets. Boom’s focus on scalable commercial airliners positions it to win the first wave of trans‑Atlantic service; Astro’s radical engine and fuel innovations could deliver the lowest cost per seat-mile of the three; and Hermeus’s hypersonic trajectory could reshape military logistics within this decade. Regulatory changes are already easing the path—chiefly the 2023 executive order that allows quiet supersonic flights and new FAA programs to streamline certification for sustainable aircraft. The capital outlay is growing; venture capital and strategic corporate sponsors are increasingly interested in faster, greener mobility. If the current pace holds, travelers could book a non‑booming, Mach 1.7 flight from Los Angeles to Paris in 2033, and by the 2040s see sub‑2‑hour trips across oceans. The shift would create new regional hubs, revive global sports leagues, and turn places like Sydney into weekend getaways. In an age where average commuting time rivals the speed of a highway, the next decade of aviation promises to reinstate the thrill of flight—making it faster, safer, and more affordable than any era before. The dawn of Supersonic 2.0 is not simply a technical triumph; it is a cultural leap toward a truly interconnected world. }