Hop Aero has raised $11 million in a seed funding round led by Initialized Capital, with participation from Y Combinator, Lunar Ventures, System.One and Outsized Ventures. The financing was announced on September 30, 2026, following the company’s participation in Y Combinator’s Summer 2026 batch.
Founded in 2024 by Matija Milenovic and Jacob Balaj, Hop Aero is an Orange County, California-based aerospace and defense startup developing rocket-powered systems for rapid cargo delivery. Its Rook vehicle is being designed for point-to-point delivery into austere and contested environments.
Rook is designed to carry up to 250 kilograms over distances of up to 750 kilometres in about 15 minutes. The autonomous vehicle is intended to launch from a standard shipping container, travel at hypersonic speeds and land without relying on conventional runway infrastructure.
According to Payload, the $11 million financing combines capital Hop Aero raised before and during its Y Combinator programme and was structured through SAFEs. The new funding will support development of the full-scale Rook 2 vehicle, which the company is targeting for a first flight in mid-2027.
Hop Aero has already completed a tethered prototype test, hot-fired its engine, conducted a static fire of a half-scale Rook vehicle and demonstrated drone deployment from its payload bay. Initialized Capital highlighted these technical milestones in announcing its investment.
The company also received a $1.25 million US Air Force Small Business Innovation Research Phase II award in 2025 for its Rapid Operations Over Kilometers programme, which focuses on reusable rocket-powered cargo delivery.
