Hermeus
AJ Piplica
Overview
Hermeus is a defense aviation company focused on rapidly designing, building, and flight-testing high-Mach and hypersonic aircraft for national-security missions. Its Quarterhorse program is progressing through a series of unmanned demonstrators to unlock high-speed flight — Mk 2.1 broke the sound barrier in May 2026, becoming the first privately-developed unmanned supersonic jet — while the Chimera engine architecture underpins Darkhorse, the reusable hypersonic UAS Hermeus aims to field for defense customers.
Main Products
An iterative program of unmanned, remotely piloted test aircraft designed to unlock high-speed flight one step at a time. Hermeus says the Quarterhorse program spans four aircraft, each purpose-built to validate a specific technical challenge and feed the next build.
Mk 1 flew at Edwards AFB in May 2025. Mk 2.1, roughly F-16-sized and powered by a Pratt & Whitney F100, flew in February 2026 and on its third flight from Spaceport America hit Mach 1.21, becoming the first privately-developed unmanned supersonic jet. Hermeus says Mk 2.2 and Mk 2.3 are already in build.
A multi-mission reusable hypersonic uncrewed aerial system (UAS) designed for defense and national security missions including ISR and strike in contested environments. Powered by the Chimera II TBCC engine.
Darkhorse remains the defense product Hermeus is building toward as Quarterhorse expands the validated flight envelope and Chimera II matures around the Pratt & Whitney F100 core.
A planned Mach 5 commercial hypersonic airliner that would carry approximately 20 passengers at 90,000+ feet altitude, cutting transatlantic flight times from 7 hours to 90 minutes. Represents Hermeus's long-term commercial vision.
Still a long-term aspiration rather than a near-term program. Hermeus is currently prioritizing defense aircraft, Quarterhorse flight testing, and propulsion maturation.
What's Next
El Segundo prototyping expansion and Atlanta production ramp
The company has said it is growing its prototyping footprint with a new headquarters in El Segundo while the Atlanta facility shifts toward production, a sign that hardware throughput and manufacturability are becoming central execution priorities.
Operations & Revenue
Actively flight-testing Quarterhorse with two successful first flights completed and a supersonic campaign underway for Mk 2.1. Hermeus says it is moving from prototyping toward mission-ready high-Mach platforms, expanding prototyping in El Segundo while shifting the Atlanta site toward production.
Revenue Streams
Hermeus' near-term business is centered on U.S. government and national-security work while it matures Quarterhorse, Darkhorse, and its propulsion stack.
Key Metrics
Timeline
On its third test flight from Spaceport America over the White Sands Missile Range, Quarterhorse Mk 2.1 reaches Mach 1.21 (~930 mph), becoming the first privately-developed unmanned supersonic jet and, per Hermeus, the fastest unmanned aircraft flying today. The flight comes 364 days after Mk 1's maiden flight and roughly three months after Mk 2.1's first flight.