Can Group 2 UAS Deliver Group 3 Performance?

Why longer endurance could move more missions into a smaller, more scalable class of unmanned aircraft.

UAS capabilities are advancing rapidly, but operational demand is growing even faster, creating a widening gap between what missions require and what current platforms can deliver. 

Larger Group 3 and above (55-1320lbs) aircraft offer range, endurance and payload, but they are expensive, and demanding to operate and maintain.

Smaller Group 2 (20-55 lbs) systems can be deployed in much greater numbers, but their mission range and time on station are often limited by a major constraint - energy.

This raises an important question: What if Group 2 aircraft could deliver more of the reach and persistence normally associated with larger platforms, without losing the advantages of being small and numerous?

Why Group 2 Matters

Group 3 core capabilities are irreplaceable. Some missions will always require large payloads, high altitude, long-range sensors or severe-weather capability.

The opportunity is to move the missions that do not require those capabilities into a smaller class. That could include persistent ISR, target acquisition, maritime surveillance, light strike, communications rely, decoy operations, collaborative sensing and.

If Group 2 systems can reach far enough to remain operationally relevant, the same budget can put many more aircraft into the battlespace - expanding area coverage, enabling more simultaneous missions and reducing the operational impact of losing any single aircraft. 

Extending the range of a small aircraft is not straightforward. More fuel, more equipment and more structure add weight. Larger engines add complexity. Eventually, the aircraft begins moving toward the very class it was supposed to complement.

The challenge is to extend the reach of Group 2 without giving up the characteristics that make it valuable in the first place.

Three Operational Environments, One Requirement

Different missions place different demands on the aircraft, but endurance remains critical.

Indo-Pacific

The Indo-Pacific creates a fundamental range-versus-quantity problem. Long-range platforms can cover greater distances, but they are relatively scarce. Smaller systems can be deployed in numbers, but their limited reach makes persistent coverage across dispersed islands, ships and expeditionary positions difficult.

A more capable Group 2 layer could distribute ISR, relay, targeting and other missions across many launch points instead of concentrating them on a few high-value aircraft. [2] [4] In this environment, operational strength comes from numbers: enough systems to cover more locations, sustain more missions and absorb losses without losing capability. 

Middle East

Operations around the Strait of Hormuz and Gulf of Oman highlight a different challenge: maintaining a persistent presence in a contested environment without tying up or risking high-value aircraft.

Recent operations in Iran have shown the cost of relying on expensive platforms for prolonged missions in areas where air superiority cannot be maintained continuously. Smaller Group 2 systems, deployed in larger numbers, can provide a persistent local presence and support ISR, targeting and other missions while reducing the exposure of more expensive assets.

The opportunity is to maintain enough aircraft over the area for long enough to create persistent local air presence and mass without compromising the primary mission of higher-end platforms.  [5]

Ukraine

Ukraine highlights the importance of combining range with mass. The battlefield requires persistent coverage and the ability to respond to targets that are constantly changing - from people and vehicles to radar and other mobile systems. Cheap, short-range drones can be deployed in large numbers, but their limited reach restricts how far that mass can be brought to bear.

At greater distances, the options become much more limited. Long-range strikes have traditionally depended on larger UAVs, manned aircraft or other high-end systems. Ukraine's 2025 Operation Spiderweb demonstrated what can be achieved by moving small drones close to their targets before launching them, allowing relatively inexpensive systems to reach aircraft deep inside Russia. It was a highly complex operation, and not a model that can simply be repeated at scale.

The broader opportunity is to give smaller Group 2 systems the range to bring that kind of mass into the battlespace without first having to move the launch point close to the target. Long-range Group 2 systems could put many more aircraft within reach of distant areas, allowing persistent coverage and attacks against a much wider set of targets. [6] [7]

The Energy Problem

For small aircraft, this is where propulsion becomes critical. Electric propulsion offers many advantages: high efficiency, simple mechanical architecture, instant response, low maintenance and low acoustic signature.

But batteries have a fundamental limitation: their energy density is far below that of liquid fuel.

Advanced lithium-metal research cells have demonstrated approximately 350 Wh/kg, while complete fielded battery packs are lower once packaging, protection, thermal management and reserves are included.

Gasoline contains roughly 12 kWh/kg before conversion losses. Even after accounting for the lower efficiency and additional hardware of a combustion engine, liquid fuel retains a major energy advantage for long-duration flight. [8] [9]

This creates a familiar trade-off. Electric propulsion is excellent for how the aircraft operates. Fuel is excellent for how long it can operate.

Why Hybrid Changes the Equation

Hybrid propulsion offers a way to stop treating this as an either-or choice. A battery and electric motor can provide the characteristics that matter most during launch, maneuvering, quiet operation and recovery.

A fuel-powered engine can provide the sustained energy needed for cruise and extended time on station.

Depending on the architecture, the engine can mechanically drive the propeller, generate electrical power, or do both. [11]

The mission can therefore be divided according to what each energy source does best:

• Electric: launch, vertical lift, maneuvering and low-signature operation

• Fuel: efficient cruise and long-duration flight

• Battery: stored energy for high-power or sensitive mission phases

• Hybrid Energy Management: balancing propulsion and onboard electrical demand throughout the mission

  
  

This approach does more than increase endurance. It can change what a Group 2 aircraft is capable of doing operationally.

Table 2. Operational capabilities enabled by greater Group 2 persistence and reach

Mission area	Shift potential	Operational effect
Persistent ISR and maritime search	High	More simultaneous sectors and overlapping coverage without consuming a large platform for every orbit.
Communications relay and network extension	High	Distributed airborne nodes can extend connectivity and reconfigure after losses.
Target acquisition and tracking	High	Numerous aircraft can maintain custody, hand targets between nodes and support sensor-to-effector chains.
Decoy, electronic support and collaborative sensing	High	Mass and autonomy create multiple viewing geometries and complicate enemy detection and targeting.
Light strike and loitering effects	Medium–high	Longer reach and time to search expand target access while compact launch systems support quantity.
Heavy strike, large multi-sensor payloads and severe-weather missions	Low	These remain Group 3-and-above missions because payload, structure, altitude and environmental tolerance dominate.

Not every Group 3 mission needs to become a Group 2 mission. But if enough of them can, the effect on the overall force can be significant.

Beyond Endurance

The value of a more capable Group 2 aircraft is therefore not measured by endurance alone. It is measured by what that endurance enables.

• More time on station means fewer recovery and relaunch cycles.

• More range means greater access from dispersed launch points.

• More aircraft in the air means wider coverage and greater redundancy.

More distributed nodes give autonomy something much more valuable to work with: a larger network.

Instead of relying on a few highly capable platforms, the force can distribute sensing, communications and effects across many aircraft.

Losses become less catastrophic. Coverage becomes easier to maintain. Larger platforms can focus on the missions that genuinely require them.

The Engineering Challenge

Engine start must be reliable across operating conditions. Heat and vibration must be managed. Fuel and batteries must be integrated safely. The system must transition between operating modes without compromising flight stability. And all of this has to fit within the size, weight and cost constraints that make Group 2 attractive in the first place.

That is why the relevant performance metrics extend beyond maximum endurance: launch time, logistics footprint, maintenance burden, reliability and cost per effect.

Conclusion

The future UAS fleet is unlikely to be defined by choosing between small aircraft and large ones. It will be defined by how effectively the two layers work together.

Group 3 and larger platforms will continue to provide capabilities that smaller aircraft cannot match. But if Group 2 systems can combine their natural advantages of size, cost, and quantity with significantly greater reach and persistence, they can take on a much larger share of the mission load.

Hybrid propulsion offers a practical path to that capability. By combining the responsiveness and low signature of electric propulsion with the energy density of liquid fuel, it can help turn Group 2 from a short-range tactical layer into a more persistent, distributed, and scalable part of the force.

The objective is not to make a smaller aircraft behave exactly like a larger one. It is to make a smaller aircraft capable of doing more of the missions that matter.

[1] U.S. Army, “Army Counter-UAS 2021–2028,” Military Review, March–April 2021. Includes the Army UAS group categorization. Source

[2] U.S. Department of Defense, “Unpacking the Replicator Initiative,” remarks by Deputy Secretary Kathleen Hicks, September 6, 2023. Source

[3] U.S. Navy, Navy Shipbuilding Plan, May 2026. Describes unmanned systems as enabling lower-cost precision mass, distributed sensing and attritable employment. Source

[4] U.S. Department of Defense, Military and Security Developments Involving the People’s Republic of China 2024. Source

[5] U.S. Office of Naval Intelligence, U.S. Maritime Advisory 2024-006, threats to shipping in the Gulf of Oman, Strait of Hormuz and surrounding waters. Source

[6] U.S. Army, “Russia’s Changes in the Conduct of War Based on Lessons from Ukraine,” Military Review, September–October 2025. Source

[7] NATO Joint Analysis and Lessons Learned Centre, Powering the Front: Tactical Energy in Ukraine, March 2026. Source

[8] U.S. Department of Energy, “Battery500: Progress Update,” May 19, 2020. Source

[9] Argonne National Laboratory, GREET fuel-cycle data and gasoline lower-heating-value assumptions. Source

[10] U.S. Department of Energy, Alternative Fuels Data Center, “Maintenance and Safety of Electric Vehicles.” Source

[11] D. Jimenez et al., “Evaluation of Series and Parallel Hybrid Propulsion Systems for UAVs,” Aerospace 9, no. 2 (2022): 63. Source