Hop Aero closed an $11 million seed round led by Initialized Capital on September 30, with backing from Y Combinator, Lunar Ventures, System.One, and Outsized Ventures, along with strategic angels Paul Graham and Jason Miller. The Orange, California-based startup is developing autonomous rockets designed to deliver cargo to contested military zones at hypersonic speeds, according to Payload.
The company declined to disclose its valuation. The entire round was structured as SAFEs, combining capital raised before and during Hop Aero's Summer 2026 Y Combinator cohort.
At the heart of Hop Aero's pitch is a straightforward military problem: getting supplies to dangerous places, fast. Traditional airlift falls apart when adversaries control the skies or when runways have been destroyed. The startup's answer is the "Rook," a vehicle capable of carrying 250 kilograms up to 750 kilometers in roughly 15 minutes via suborbital trajectory. It launches vertically from a standard 40-foot shipping container and lands on unprepared surfaces, sidestepping the need for infrastructure.
"We're building rockets that deliver cargo to contested environments... suborbitally point to point at hypersonic speed," CEO Matija Milenovic explained on the Deeptech Decoded podcast in August 2026.
The U.S. military has already shown interest. The Air Force Research Laboratory awarded Hop Aero a $1.25 million SBIR Direct-to-Phase II contract in September 2025 under the title "ROOK: Rapid Operations Over Kilometers," with work extending through October 2026, according to HigherGov contract records. That contract aligns with broader Pentagon efforts exploring rocket cargo, including AFRL's Rocket Cargo Vanguard program and Space Force research on point-to-point delivery, both visible in fiscal 2026-2027 budget documents.
The Team Behind the Rockets
Milenovic brings an unusual resume to the venture. He previously founded porkchop, a satellite electric propulsion company that flew hardware on SpaceX's Transporter-3 mission, and logged time as a systems engineer at hypersonic startup Destinus. He also scaled loitering-munition production for Ukraine and earned a master's in aerospace engineering from KTH.
Co-founder and CTO Jacob Balaj's background, detailed in the company's Y Combinator profile, traces a different arc through aerospace. He served as an avionics specialist on the MV-22 Osprey in the Marine Corps before joining SpaceX, where he worked on Falcon 9 and Falcon Heavy, including the booster refurbishment program. Stints at Virgin Orbit, Masten Space Systems (on NASA's Commercial Lunar Payload Services lander integration), and SpinLaunch followed.
Still Grounded, For Now
As of September 30, Hop Aero has not launched anything untethered, Payload reported. Over the summer, the seven-person team designed a 3D-metal-printed engine using the company's "hopOS" software, conducted hot-fire tests at Infinity One Oklahoma Spaceport in Burns Flat, and ran a static fire of a half-scale Rook prototype. They also demonstrated a ground test deploying four drones from the payload bay.
Infinity One, formerly the Oklahoma Air & Space Port, received its FAA spaceport license and has been positioning itself for suborbital operations, according to an April 2026 state announcement.
"We're going to be moving into our full-scale Rooks," Milenovic told Payload. The company is targeting mid-2027 for the first flight of "Rook 2," the full-scale vehicle.
A Crowded Field, Different Approach
Hop Aero is not alone in chasing rocket cargo contracts. Stoke Space holds a Defense Innovation Unit contract, awarded in 2024, to prototype "responsive space delivery" for point-to-point cargo to, through, and from space. Astra secured a separate DIU award in October 2024 for similar work, TechCrunch reported.
But Hop Aero's strategy diverges. Rather than orbital or exoatmospheric delivery, the company focuses on suborbital hops inside the atmosphere. That could simplify regulatory approval and reduce mission complexity for shorter-range logistics, though it also narrows the addressable distance.
Investor Dynamics
The fundraising process surprised even the founders. "We ended up raising more than we initially planned," Milenovic told Payload. "We were really fortunate to be able to turn down a lot of really good funds."
The round drew a mix of traditional seed investors and defense-focused capital. Lunar Ventures, System.One, and Outsized Ventures also backed Hop Aero's pre-seed round in March 2025 alongside Silicon Roundabout Ventures, according to a LinkedIn post by Pepe Borrell of Silicon Roundabout on October 1, 2026. Y Combinator's involvement came through the Summer 2026 batch.
Hop Aero plans to deploy the fresh capital toward building and flying Rook 2. If the mid-2027 timeline holds, the startup will soon learn whether its bet on suborbital logistics can move from test stand to operational reality.
