Eyes in the sky
US Intelligence, surveillance, and reconnaissance aircraft.
By Owen Davies
Contributing Writer
The US military operates many specialized manned aircraft designed for specific functions, from fighters and bombers to transports and medevac helicopters. None are so focused on specific missions as intelligence, surveillance, and reconnaissance (ISR) aircraft. Some collect communications intelligence (COMINT) or signals intelligence (SIGINT), some collect geospatial data (GEOINT), while others scan the skies for threats or hunt submarines beneath the waves. Some provide command and control for air, sea, and land assets. It is a rare airplane that can handle more than 2 such tasks well.
Most ISR aircraft used by US forces are adapted from a commercial platform. Boeing airliners and executive jets from Bombardier form the backbone of the fleet, customized into some of the best intelligence-gathering machines in the world. The rare exceptions include a customized Pilatus turboprop, a converted crop duster, the purpose-built E-2 Hawkeye, and the iconic U-2 Dragon Lady.
Key technology improvements
Modern ISR aircraft benefit from revolutionary advances in sensor technology. Traditional pulse radars have evolved into active electronically scanned array (AESA) systems with improved detection range, multi-target tracking, and jamming resistance. These systems detect targets at greater distances and collect position, altitude, and speed data simultaneously, improving battlefield awareness.
Advanced electro-optical and infrared (EO/IR) sensors provide high-resolution imagery in various light conditions, while increasingly sensitive SIGINT systems can detect and discriminate between signals with unprecedented precision. Data fusion software now integrate information from multiple sensors for comprehensive situational awareness (SA) across vast operating areas.
Secure, high-bandwidth communications enable real-time data sharing between aircraft and command centers, permitting faster tactical response to evolving threats. More efficient engines extend range and endurance, keeping ISR jets on station longer. And, in a recent development, artificial intelligence (AI) is processing the vast amounts of collected data, turning raw information into actionable intelligence faster than ever before.
ISR aircraft of the US Air Force
E-3 Sentry. Adapted from the Boeing 707 airliner, the airborne warning and control system (AWACS) Sentry provides command and control for air assets. Its 360º radar can detect low-flying aircraft from 200 nm as well as maritime traffic.
It can track more than 600 targets simultaneously. Secure data links enable real-time information sharing with ground stations and other aircraft.
The Sentry can patrol for 8 hours without refueling. Re-engined variants were flown by the UK’s Royal Air Force, and remain in service with France and Saudi Arabia. The E-3D can achieve 11 hours aloft, with double the range. In service with the US Air Force (USAF) since 1977, the remaining E-3s will soon be replaced by the Boeing E-7 Wedgetail.
RC-135V/W Rivet Joint. Derived ultimately from the 1950s-era Boeing 367-80 prototype airliner via the KC-135 Stratotanker, the RC-135V/W is a premier SIGINT platform carrying multiple specialized antennae and advanced ELINT and COMINT systems able to capture, process, and transmit intelligence in real time.
Operating at up to 50,000 ft with a 3900-nm range, each aircraft carries 3 pilots, 2 navigators, at least 3 electronic warfare officers, 14 intelligence operators, and 4 maintenance technicians. This large crew reflects the complexity of onboard systems and the need for immediate analysis of collected data.
Early-model Rivet Joints entered service in 1964. There are 71 heavily upgraded examples still in service. Specialized variants include 3 RC-135S Cobra Ball aircraft, which collect optical and electronic data on ballistic missiles for the Joint Chiefs of Staff. In addition, 2 RC-135U Combat Sent platforms provide strategic electronic reconnaissance to senior defense leadership and theater commanders.
U-2 Dragon Lady. The U-2 high-altitude ISR aircraft was built by Lockheed from the mid-1950s onwards. The ultimate U-2 model, the Lockheed Martin U-2S Dragon Lady, provides signals, imagery, and electronic intelligence with remarkable versatility.
Its mission equipment includes the ASARS-2A synthetic aperture radar with moving target identification, the SYERS-2C multispectral imaging system, and an optical bar film camera for high-resolution, broad-area coverage. Advanced SIGINT collects data and sends it in near real time worldwide via air-to-ground and satellite data links.
Beyond military reconnaissance, the Dragon Lady supports peacetime disaster relief, providing crucial imagery during floods, earthquakes, and forest fires. Cruising at 356 kts with a ceiling above 70,000 ft and 6000-nm-plus range, the U-2 Dragon Lady can remain aloft for more than 12 hours. Thirty-three remain active, including 5 2-seat trainers and 2 ER-2s operated by NASA. The USAF plans to retire all its U-2s by 2026, ending the legendary aircraft’s 7-decade career.
U-28A Draco. Customized from the Pilatus PC-12/45 executive turboprop, the Draco supports special ops missions, humanitarian operations, and search and rescue (SAR) missions. It carries sophisticated radio communications, IR suppression systems, and comprehensive threat warning capabilities that detect missiles, hostile fire, and lasers.
Valued for its ability to operate from short runways and semi-prepared surfaces, the Draco offers flexibility unavailable to larger ISR platforms. With 2 pilots, a combat systems officer, and a tactical systems operator, it cruises at 253 kts with a 1500-nm range and 30,000-ft ceiling. Twenty-eight are on active duty.
OA-1K Skyraider II. Starting life as the Air Tractor AT-802 cropduster, L3Harris converts it into a sophisticated ISR aircraft for USAF Special Operations Command. Designed for lower-threat environments and operating without complex support infrastructure, it will perform SIGINT, armed reconnaissance, and close air support missions.
The Skyraider II’s modular mission systems can swap different sensors and payloads as needed. It features a communications suite equivalent to an executive turboprop and Lockheed AC-130, along with EO/IR sensors and SIGINT collection systems. It can be disassembled in one day, shipped aboard a single Boeing C-17 Globemaster III, and reassembled in one day, allowing for quick theater introduction.
Sixty-two aircraft are under contract, the first entering service in March 2025. The Skyraider II cruises at 180 kts with a 1303-nm range, and can loiter for 6 hours at a 200-nm combat radius. Export approval for 22 potential overseas buyers and 15 additional countries under review suggest strong international interest in this cost-effective ISR model.
E-7A Wedgetail. Boeing’s 737 Next Generation (737NG), this will be the USAF’s next-generation airborne early warning and control (AEW&C) system. Its 360° multirole electronically scanned array (MESA) radar provides surveillance over 1.1 million sq nm, integrating data from multiple domains while commanding air, sea, and ground assets.
Advanced electronic counter-countermeasures protect it against electromagnetic threats, and refueling during flight enables missions exceeding 18 hours. A crew rest area, galley, and toilets ensure that human factors don’t limit operational endurance. The Wedgetail already serves with Australia, South Korea, Turkey, and the UK. The US has ordered 2 prototypes for delivery to the USAF in 2028, with 24 more planned by 2032.
ISR aircraft of the US Army
High Accuracy Detection and Exploitation System (HADES). This is a modified Bombardier Global 6500 that extends range of surveillance. Its deep-sensing capabilities integrate SIGINT systems, including the Pegasus ELINT sensor, and standard COMINT packages, with synthetic aperture radar and EO/IR sensors. Onboard AI analyzes collected data and secure communications systems transmit the result to ground forces in real time.
Operating at up to 51,000 ft with a 567-kt cruise speed and 7600-nm range, HADES represents a significant ISR upgrade for the US Army. Only 1 aircraft has been delivered out of 14 planned. The program is currently on hold due to a contract protest filed by L3Harris. When fully implemented, HADES will replace the legacy Beechcraft RC-12 Guardrail and MC-12W Liberty platforms.
RC-12X/X+ Guardrail. Based on the King Air B200, it serves as the US Army’s primary tactical SIGINT platform. Its Guardrail Common Sensor uses adaptive beam-forming antennae to detect, classify, and geolocate radio signals across low, medium, and high bands, transmitting precise targeting data to support tactical and operational decision-making.
Enhancements over previous models include improved avionics, glass cockpits, and structural reinforcements to extend service life. With a 310-kt cruise speed and 35,000-ft operating altitude, the aircraft has a 1720-nm range. However, it typically operates within 180 nm of ground processing facilities for missions up to 5.5 hours. The US Army currently operates 14 Guardrails, but plans to retire them this year.
MC-12S Enhanced Medium Altitude Reconnaissance and Surveillance System (EMARSS). The MC-12S EMARSS, a modified Beechcraft King Air 350ER, provides versatile ISR support to brigade combat teams. Its mission equipment includes high-definition EO/IR sensors for video surveillance, a standard SIGINT payload, and variant-specific hardware – EMARSS-V carries vehicle and dismounted exploitation radar (VADER) to track vehicles and personnel over wide areas, while EMARSS-G employs light detection and ranging (LiDAR) for geospatial mapping and detecting buried threats like improvised explosive devices (IEDs).
Two onboard work stations linked to the Distributed Common Ground System enable real-time data processing and transmission to ground forces. With a 312-kt cruise speed, 2400-nm range, and 35,000-ft ceiling, 23 EMARSS aircraft provide critical battlefield intelligence, but are scheduled for retirement in 2025 as the Army moves to jet-powered ISR platforms.
ISR aircraft of the US Navy
E-2C/D Hawkeye. Unlike most ISR platforms, Northrop Grumman’s E-2 Hawkeye was purpose-built for its role as a carrier-based early warning and command and control aircraft. It manages the battlespace for carrier strike groups, performing surface surveillance, air interdiction, close air support, and strike coordination. It supports SAR missions and serves as a communications relay.
The E-2D Advanced Hawkeye represents a generational leap with entirely new electronics, including an AN/APY AESA radar and satellite communications. Its systems include the Aegis automated detection and control system and automatic identification systems, which determine a ship’s identity, course, and cargo. With 2 pilots and 3 mission specialists, the E-2D cruises at 256 kts. It has a 1462-nm ferry range and 34,700-ft ceiling, and can remain aloft for up to 8 hours. Endurance can be extended by inflight refueling.
P-8A Poseidon. Derived from the Boeing 737NG, the P-8A Poseidon has revolutionized maritime patrol and anti-submarine warfare when it entered service in 2005. Its comprehensive mission equipment includes the AN/APY-10 high-resolution imaging radar, high-definition electro-optical cameras, and electronic intelligence detection systems. Advanced acoustic systems using sonobuoys and a magnetic anomaly detector find, identify, locate, and track submarines.
Unlike nearly all ISR platforms, the Poseidon brings substantial offensive capability. Depending on the mission, it can carry Mark 54 lightweight torpedoes, depth charges, and AGM-84 Harpoon anti-ship missiles.
Operating with a 9-person crew at speeds of up to 490 kts and altitudes up to 41,000 ft, it maintains a 1200-nm-plus mission radius with 4 hours on station – extendable by inflight refueling. The US Navy has 123 units in service at present, and 11 more were recently ordered.
Emerging trends in ISR technology
ISR capabilities continue advancing rapidly. AI and machine learning enable faster data processing, automated threat recognition, and better decision-making. They support multisensor data fusion, improving SA while reducing analyst workload. Predictive analytics and anomaly detection identify potential threats before they develop, while adaptive sensor configurations adjust to changing mission requirements.
Stealth technologies are appearing in ISR platforms, with radar-absorbing materials and optimized shapes that minimize detection. Advanced concepts like electromagnetic metasurfaces and plasma stealth promise further improvements, reducing risk in contested environments.
Unmanned and optionally-manned systems deliver persistent surveillance without risking aircrew, while swarms of drones use collective behavior to simplify complex tasks while providing built-in redundancy against countermeasures.
Multi-domain operations integrate data from air, land, sea, space, and cyber domains, providing comprehensive battlefield awareness.