# Hop Aero

> Hop Aero is a Los Angeles aerospace startup (YC S26) building Rook, an autonomous cargo rocket that launches from a standard 40-foot shipping container, flies a suborbital hypersonic arc, and lands 250 kg of cargo up to 750 km away in roughly 15 minutes - onto unprepared ground, with no runway or fixed infrastructure. Founded in 2024 by Matija Milenovic and Jacob Balaj, the company targets contested military logistics and high-downtime commercial supply runs.

- **Founded:** 2024
- **Headquarters:** Los Angeles, California, United States
- **Founders:** Matija Milenovic (Co-Founder & CEO), Jacob Balaj (Co-Founder & CTO)
- **Team size:** 6-14 employees
- **Products:** Rook, hopOS
- **Notable:** Won a $1.25M US Air Force (AFRL) SBIR Direct-to-Phase-II contract, Completed a tethered flight test of a small-scale prototype at an Oklahoma spaceport, Successfully hot-fired its proprietary rocket engine and igniter

## Products & services

- **Rook** — An autonomous cargo rocket roughly 6 meters tall that launches from a standard 40-foot shipping container, flies a suborbital arc at low hypersonic speed, and delivers 250 kg (about 550 lbs) up to 750 km in roughly 15 minutes, landing on unprepared surfaces with no runway.
- **hopOS** — In-house, AI-augmented engineering software the team used to design and iterate its rocket engine and igniter in about two months.

## Achievements

- Won a $1.25M US Air Force (AFRL) SBIR Direct-to-Phase-II contract
- Completed a tethered flight test of a small-scale prototype at an Oklahoma spaceport
- Successfully hot-fired its proprietary rocket engine and igniter
- Designed its rocket engine in roughly two months using in-house hopOS software
- Accepted into Y Combinator's Summer 2026 batch
- Came out of stealth in 2026 with a public unveiling of the Rook rocket

## Latest updates

- **2026-07** — Hop Aero came out of stealth and joined Y Combinator's Summer 2026 batch.
- **2026-06** — Publicly unveiled Rook, its autonomous hypersonic cargo rocket, across press and social channels.
- **2025-09** — Awarded a $1.25M AFRL SBIR Direct-to-Phase-II contract.

## Links

- Website: https://hop-aero.com
- LinkedIn: http://www.linkedin.com/company/hop-aero
- Twitter/X: https://x.com/Hop_Aero

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Profile page: https://yespress.io/hop-aero-yc-s26
Published by YesPress — https://yespress.io
Last updated: 2026-07-31