How Hermeus Built a Unicorn at Mach 5

Hermeus hits $1B valuation with a $350M Series C to build the US military's fastest unmanned aircraft 

18 May 2026

Hermeus, a California-based aerospace company, closed a $350 million Series C funding round on 7 April, reaching a valuation of $1 billion and bringing total capital raised to more than $500 million. The round reflects sustained investor interest in high-speed military aviation at a time of rising defence technology spending globally.

Khosla Ventures led the $200 million equity portion. Founders Fund, In-Q-Tel, and RTX Ventures also participated. The remaining $150 million was raised as structured debt, a structure the company said was chosen to preserve ownership while financing capital-intensive manufacturing.

The company is developing unmanned aircraft for the US Department of Defence capable of reaching Mach 5, five times the speed of sound. A decision to build around a modified Pratt & Whitney F100 engine, rather than a purpose-built propulsion system, has shortened development timelines and supported early government contracts.

In March 2026, Hermeus flew its Quarterhorse Mk 2.1 demonstrator at White Sands Missile Range in New Mexico. The aircraft is roughly the size of an F-16 and four times heavier than the previous test vehicle. A supersonic follow-on programme is under development.

Proceeds from the round will fund an expanded manufacturing facility in El Segundo, California, and continued work on both the Quarterhorse testbed and the Darkhorse drone programme. The company employs close to 300 people and plans to grow that number as production increases.

Defence technology investment exceeded $9 billion globally last year. Hermeus occupies a position where institutional aerospace capital and venture-backed development timelines converge. Chief executive AJ Piplica has said the company expects test failures and treats them as part of the development process, an approach modelled on commercial space programmes.

Certification timelines for Mach 5 platforms have not been set. Commercial applications remain distant. The pace of hardware iteration that underpins the company's development model also carries engineering risks that more traditional procurement programmes are built to manage carefully.

Two completed test flights and a billion-dollar valuation mark a shift from concept to active programme. Whether the approach scales to full production remains the central question.