Defense Startups funded by Y Combinator (YC) 2026

Hop Aero is building rocket cargo vehicles that deliver to contested environments hundreds of miles away in minutes. Our rockets fly point-to-point into the most austere locations at hypersonic speeds. Hop Aero's goal is to provide the U.S. and allies the asymmetric advantage that deters a future major conflict.

Arlo Industries is building a network of sensors that precisely tracks stealthy drones and aerial threats better than radars. This capability does not exist yet because traditional radars are built on past war doctrines designed to protect single, centralised assets. Modern warfare, however, demands wide-area, persistent coverage that is both passive and economically scalable. By utilising a mesh architecture, Arlo Industries unlocks unprecedented asymmetric economics. The network is fundamentally built to scale: the cost of adding sensors grows linearly, but the tracking accuracy increases exponentially, delivering highly resilient, persistent coverage for a fraction of the cost of legacy systems. Deo founded Arlo Industries after spending over 6 years in the Israeli defence ecosystem, where he lived through multiple conflicts and experienced the Iron Dome and other systems in action against ICBMs and the infamous Shahed drones. Learning exactly how these defence systems could be improved after a Shahed exploded close to his apartment, he built Arlo Industries around the core philosophy that conflict should be concise & precise. The people behind Arlo1 includes a PhD in drones and autonomy and military experts. Arlo Industries has actively showcased this technology directly to Ukrainian militaries on the frontlines, as well as to operators across Europe and the USA.

GUILD is a Neoprime contractor automating defense supply chain end-to-end by vertically integrating with our supplier partners. We integrate artificial intelligence, contracting operations, and capital to source, fund, produce, and deliver defense contracts end-to-end. Operating across the U.S. and NATO markets, we bridge global manufacturing capacity with defense demand and execute with the speed and precision of an AI-driven system. Our mission is to build a modern, new generation defense contracting institution where technology and production operate as one.

Surtr builds ParallaxOS, the open operating system for counter-UAS. It takes sensor data from any radar, RF detector, camera, or acoustic array and fuses it into a single unified picture with AI-driven threat classification and engagement recommendations. One interface, any hardware, human in the loop.

Tenet Industries is building low-cost mass-producible defense systems, starting with attack drones. We're using design-for-manufacturing and first principles to reimagine how a defense product is developed and manufactured. We begin with the manufacturing, then solve all the inefficiencies and difficulties in the firmware/software. This allows us to hyperscale production in multiple defense categories such as strike drones, loitering munitions, jammers, radars, etc. Our first product is a kamikaze quadcopter. It assembles in two minutes and has half the parts to comparable systems.

We are building the next generation of underwater defense systems: autonomous swarms of modular marine drones to secure naval assets and coastal infrastructure against evolving underwater threats.

We have sold $1.6m of systems to the DoW. Multiple systems delivered to the DoW. Our first product - EDDA - is a counter drone system - small, low power, low cost fully autonomous-capable. It's designed to be used on vehicles, bases, or carried - to stop group 1 suicide drones. We have multiple contracts, sales, etc. We have 3 more products with demand in various stages of development. More details at https://9mothers.com

DAIVIN! builds tankless dive gear that unlocks breath autonomy in extreme environments. Starting from underwater environment our mission is to remove the need for dangerous, heavy and bulky oxygen tanks in space, air and on land and replace them with water!

We engineer inexpensive, autonomous strike drones designed to operate in the most contested combat environments on Earth! By combining true hardware modularity with an agentic control system that lowers cognitive load on operators, we enable faster upgrades, broader adoption, and more than 2x reduction in lifecycle cost. Our customers and partners include the UK Royal Marine Commandos, several other units in the UK, and 4 other NATO forces, and we are currently shipping prototypes for iterative feedback. Think of us as Anduril, but with worse weather, and better banter.

We provide defense companies with simulation infrastructure to train and validate autonomous systems.

Icarus is building the modern-day U-2 spy plane. Our autonomous solar aircraft fly at 60,000 feet for weeks at a time, eventually months and years, above weather and below satellites. They deliver persistent intelligence and connectivity for the military at a fraction of the cost of existing systems. The stratosphere is the forgotten frontier.

Albacore Inc. builds mass-producible long-range drone submarines. In the era of autonomous warfare, we support military operators with underwater systems that can traverse oceans and be deployed at scale.

Perseus Defense is building a mass-manufactured Counter UAS solution for the Department of Defense and Department of Homeland Security. Current solutions are one-to-one, too dangerous for use on U.S. soil, and orders of magntiude more expensive than the threats they defeat. Our self-guided missile platform is man-portable and multi-domain capable. It senses, engages, and eliminates threats with drastically reduced cost per engagement over existing kinetic solutions. Solving this critical national security problem requires understanding complex DoD needs along with actual rocket science including aerodynamics, guidance, navigation, control, and much more. Jason and Steve met at Penn State while they pursued their PhD and MS in aerospace engineering, respectively. Their past experiences designing space helicopters for NASA, making Boeing airliners land autonomously, controlling swarms of unmanned autonomous systems, teaching aerospace engineering at Stanford, winning multiple ONR and DOE engineering competitions, and founding an international drone competition makes them the perfect team to create transformative solutions protecting our service members. "If you build this, it will be mandatory equipment for every truck, boat, and convoy in the U.S. Military. We're talking thousands of units." - Former DoD Procurement Officer The White House just released Executive Order, "Unleashing American Drone Dominance" which adds billions of dollars, government support, and streamlined regulations to enable the development of our product. Traction: Jason and Steve used more than 100 end-user interviews across the DoD and DHS to shape the product to something of critical need to both boots on the ground and DoD purchasers. In 8 short weeks following a strict 2-week design-build-test cycle, the team has gone through 4 major guided missile iterations with over 30 live-fire flight tests. They were invited to Ft. Hood to present their platform to the 1st Cavalry Division, and also briefed the Pentagon and U.S. congressmen on current U.S. vulnerabilities to advanced drone technology. Perseus Defense is actively standing up cooperative research agreements with U.S. Army DEVCOM's Applied Research Laboratory, Aviation and Missile Center, Armaments Center, and High Performance Computing Modernization Program.

Conntour enables organizations to query thousands of security cameras using natural language. Users can search past footage (“Find a man with tattoos on his left arm”), configure real-time alerts (“Notify me if someone climbs over the wall”), and extract data (“How many pickup trucks entered yesterday?”). Unlike traditional video analytics limited to pre-defined parameters (like a weapon, bag, or license plate), Conntour supports unlimited, highly specific scenarios described in plain language. This enables a single human to monitor thousands of cameras. Matan (CEO) worked with security cameras for years, leading video surveillance in the Israeli Military. Tomer (CTO) is a second-time founder and former director of engineering. Our team also includes computer vision experts from Israel’s elite 8200 intelligence unit and former top officials from the Mossad. Conntour is backed by General Catalyst, selected for the first-ever Palantir fellowship, and advised by Bob Flores, former CTO at the CIA.

DeepNight is building the next generation of night vision with AI.

Detect and safely block unwanted drone intrusions. Track down and arrest unauthorized operators. Developed by experts from Israel Defense Forces and currently serving more than 25 countries, ApolloShield is the world leader in detecting and blocking drone intrusions, as well as tracking down and arresting unauthorized drone operators.