[23] The new airframe introduced modified diverterless supersonic inlet (DSI) intakes, stealth coating, streamlined underwing fairings, and redesigned vertical stabilizers.

Analysts noted new equipment and devices for multi-role operations, such as integrated targeting pods for precision-guided munition, and six additional passive infrared sensors can also be spotted around the aircraft.

[43] In January 2021, Aviation Industry Corporation of China released computer renderings of the twin-seat variant of the J-20 fighter in celebration of the 10th anniversary of the jet's maiden flight.

[48][49] The twin-seat design allows the possibility for the second operator to coordinate attacks and reconnaissance missions from other friendly aircraft via networking or unmanned combat aerial vehicles (UCAVs) linked via "loyal wingman" systems and sensors.

The advantage of a second operator includes the potential for better interpreting and exploiting the enormous sensory data that could overload the limited cognitive and processing capacity for a single human, especially in a contested air combat environment.

The new variant was painted in yellow primer and different from previous J-20 aircraft in airframe design, with a low-profile blended canopy, aiming to optimize transonic flight performance and maneuverability.

[60] In October 2023, the Pentagon reported that PLAAF was upgrading the J-20, with enhancements such as extended weapon-carrying capability, thrust vectoring nozzles, control systems for unmanned aircraft teaming, and WS-15 high-thrust engines.

The designer claims such a combination allows the use of a smaller wing, reducing supersonic drag without compromising transonic lift-to-drag characteristics that are crucial to the aircraft's turn performance.

[65][66][70] The use of a bubble canopy, extensive flight-control surfaces, and canard configuration for angle-of-attack control indicates J-20's intention to operate in air-superiority missions and within-visual-range engagements.

[115] Analysts noted that the J-20's airframe employs a holistic approach to reduce its Radar cross-section (RCS), uniquely combining canard wings with leading edge root extensions (LERX).

Additional low-observable features include a flat fuselage bottom holding an internal weapons bay, sawtooth edges on compartment doors, mesh coverings on cooling ports at the base of the vertical tails, embedded antennas, and radar-absorbent coating materials.

[123][124] Lockheed Martin employed canards on a stealth airframe for the Joint Advanced Strike Technology (JAST) program during early development before dropping them due to complications with aircraft carrier recovery.

[134][135] Analyst Justin Bronk from Royal United Services Institute noted that Chinese were possibly flying the J-20 with radar reflectors during peacetime for safety and training purposes due to the potential for accidents and identification from other aircraft or ground installations.

[136] In a more recent report, Bronk also states that even with limited stealth, J-20 could hide and strike enemy critical platforms in an airspace with background clutter caused by non-stealth fighters and other electromagnetic noise.

[145][146] On 16 January 2014, the third J-20 prototype was revealed, showing new intakes, embedded engine nozzles, and stealth coating, as well as redesigned vertical stabilizers, and an Electro-Optical Targeting System.

But it still faced a series of technical challenges that needed to be tackled, including the reliability of its WS-15 engines, the aircraft's flight control system, stealth coatings, hull materials, and infrared sensor.

[153] In September 2017, a newly built J-20 prototype (numbered "2021") was flight testing with Chinese-made WS-10 Taihang engines, featuring sawtoothed serration edge on its afterburning nozzles.

[160][164] Analyst Rick Joe speculated the initial production batch of the revised J-20 model might enter service with WS-10 or WS-15 engine, depending on the circumstances surrounding the development.

[167] In October 2017, Chinese media reported that CAC initiated the serial production for the J-20 and is on a path towards achieving full operational capability with the People's Liberation Army Air Force (PLAAF).

[77] Asia Times reported that PLAAF had prioritized deploying J-20s for airbases close to China's maritime border, and believed J-20's long combat range is well-suited for high-speed interceptions, strategic area defense, and long-range strike missions over the First- and Second-island chain.

Internal upgrades include an overhaul of software, avionics, and sensor suites, refines in airframe material and structures, improvements in signature reduction, and significant advancements in power and thermal management.

[47][46] The twin-seat design allows the possibility for the second operator to conduct airborne early warning and control (AEW&C) missions, which J-20 would leverage its avionics and networking capability to provide battlespace surveillance, battle management, and intelligence analysis.

[204][207] With increased automation and artificial intelligence in the aircraft system, the two men crew would likely be able to delegate more complex AEW&C tasks, absorb information, and make tactical decisions.

[208] In October 2022, Chinese media showcased the concept of the J-20 two-seater controlling stealth Hongdu GJ-11 unmanned combat aerial vehicle, and the back seat is designated for the weapons officer.

[214][215][216] Abraham M. Denmark of the Center for New American Security in Washington, along with Michael Swaine, an expert on the PLA and United States–China military relations, explained that senior officials are not involved in the day-to-day management of aircraft development and were unaware of the test.

[213][91] Robert Gates downplayed the significance of the aircraft by questioning how stealthy the J-20 may be, but stated the J-20 would "put some of our capabilities at risk, and we have to pay attention to them, we have to respond appropriately with our own programs.

[224][225][226][227][228] After the deployment announcement in 2018, several analysts noted that the experience that the PLAAF will gain with the J-20 would give China a significant edge over India, Japan, and South Korea, which have struggled to design and produce their own fifth-generation fighters on schedule.

[234] In March 2022, the United States Air Force (USAF) general Kenneth Wilsbach described J-20s were flying professionally and he is "relatively impressed" with the Chinese command and control structure and AEW&C capabilities after confirming two nations had an encounter in South China Sea.

[91] Matthew Jouppi of Aviation Week noted the ill-informed assumptions that existed in defense circles and argued that the United States has not adequately addressed threats posed by the increasing Chinese airpower.

The indigenization of critical components such as the jet engines, avionics, radar, and weapons systems helped to fast-track the production rate, and constant tests and upgrades fixed tethering and performance issues between batches.