Reliable Robotics reaches unicorn status as Series D extension adds $115M in equity

The autonomous flight startup's Series D now totals $160 million at a post-money valuation of approximately $1 billion

Reliable Robotics has joined the unicorn club. The Mountain View, California-based developer of autonomous flight systems extended its Series D round with $115 million in equity and $25 million in debt.

The round now totals $160 million. Nimble Partners led it, and the company’s post-money valuation comes to approximately $1 billion.

The company announced the raise on April 21, 2026. It says the capital will go toward three priorities.

The first is scaling production of its Reliable Autonomy System, or RAS. The second is moving its FAA certification forward for uncrewed commercial cargo flights.

The third is hiring people and building out facilities to support both efforts.

RAS is designed to automate the full arc of a flight. That includes taxiing, takeoff, the enroute portion and landing.

The company’s focus is fixed-wing aircraft. It is not building drones or air taxis.

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The equity-plus-debt structure of the extension is worth noting. Mixing $115 million in equity with $25 million in debt lets the company add capital without giving away as much ownership as an all-equity raise would require.

Reliable Robotics was founded in 2017 by veterans of SpaceX and Tesla . It has now raised more than $300 million in total since launch.

The company says it holds more than 200 commitments for its systems from commercial and military customers.

Reliable holds a US Air Force contract valued at roughly $17.4 million.

It also has NASA SBIR Phase III agreements covering testing and the development of standards. SBIR stands for Small Business Innovation Research, a federal program that funds startups working on technology the government wants. Phase III agreements generally mean the work has moved past early research toward practical application.

The company has also flown demonstration flights under the Department of Transportation’s eIPP program. Those flights are part of its push toward regulatory approval for remote and autonomous missions.

Reliable says its employee base has nearly tripled since its previous funding round.

It has also added senior leadership. Marc Stoll joined as chief financial officer, and Russ Elmer came on as general counsel.

The company is conducting operational testing as it moves into mid-2026. That testing feeds directly into the certification process it hopes to complete.