Two Chengdu J-20 stealth fighters headlined China’s Airshow China in Zhuhai on Tuesday, flying for just a few minutes, Reuters reports.

But Justin Bronk, a research fellow specializing in combat airpower at the Royal United Services Institute, said the display left many questions unanswered.

On paper, the J-20 represents a “big leap forward in terms of the capabilities of the PLA (People’s Liberation Army) have on scene,” Bronk said.

Compared with the US’s fifth-generation fighter jets, the F-22 and the F-35, the J-20 has “longer range, more internal fuel capacity, and larger internal weapons capability,” Bronk said.

This combination of factors presents a real risk to US forces in the Pacific. Long-range, capable strike fighters like the J-20 put the US AWACS, or airborne warning and control system, as well as “refueling tankers, and forward bases at risk much more than current types if flying in relatively large numbers” should any kind of kinetic conflict flare up in the Pacific, Bronk said.

David Goldfein, the chief of staff for the US Air Force, told Breaking Defense he was not overly troubled by the new Chinese jet.

"When I hear about F-35 versus J-20, it's almost an irrelevant comparison," Goldfein said in August.

Indeed, nothing indicates that the Chinese have built in the type of hyper connectivity and sensor fusions that make the US's fifth-generation fighters so groundbreaking. Of the F-35 in particular, Bronk said: "Pilots are not spending a huge amount of time managing inputs - the machine does it for him. It produces one unified picture, which he can then interrogate as required."

F-35 cockpit

Foto: F-35 pilots have unprecedented 360-degree visibility, can even see through the airframe with cameras, and can fire missiles at targets they aren't even facing. source Staff Sgt. Darlene Seltmann/US Air Force

This gives F-35 pilots a situational awareness the Chinese most likely leverage in combat.

But what exactly goes on under the hood of the J-20 remains a mystery. What is known is that the Chinese have managed to steal a considerable amount of info from US defense aviation projects.

"We don't know how much F-35 technology the Chinese have managed to steal," Bronk said, adding that while it was "impossible to say for sure" what the J-20 is capable of, common sense dictates that the "the sensor fusion and network integration is significantly behind what the US has managed with the F-35 and F-22.

"This is purely based on the fact that sensor fusion has taken the most effort, time, and money," he continued.

But one-on-one combat scenarios or feature-for-feature comparisons don't capture the real threat of the J-20.

Long-range stealth fighters, if fielded in large numbers along with older Chinese aircraft, surface-to-air missile batteries, radar outposts, missiles, and electronic-warfare units, present another wrinkle in an already complicated and fraught operating envelope for US and allied forces in the Pacific.

But is it real?

Chengdu J-20

Foto: Not really J-20, but a rendering of it. source Alexandr Chechin/http://en.wikipedia.org/wiki/Chengdu_J-20#mediaviewer/File:J20_impside_art.JPG

Whether the Chinese will actually be able to field this plane by 2018, as Beijing has projected, remains the real question.

Bronk pointed out that it took a decade between US developers building a flying model of the F-22 and getting real, capable F-22s in the air. Even if the Chinese have accelerated the process through espionage, Bronk says, "We know how much money and time it takes to make a lethal and effective fighter like the F-22," and it's "very unlikely that China is that far along."

Additionally, the J-20s in Zhuhai flew for only about one minute. They didn't do low passes. They didn't open up the weapons bay. They didn't do much except fly around a single time.

F-35 and F-22

Foto: A real, operational formation of F-22s and F-35s.sourceUSAF

"We learned very little," Greg Waldron, the Asia managing editor of FlightGlobal, told Reuters. "We learned it is very loud. But we can't tell what type of engine it has, or very much about the mobility."

Bronk speculates that the models on display at Airshow China were not much more than showpieces: "It's possible that the aircraft that were shown are still instrumented production aircraft," or planes with "loads of sensors to monitor performance" instead of in a combat-ready formation.

Bronk points out that the aircraft most likely flew with underpowered engines and not the engines that would fly on the final version. "Engine performance is a key function of any aircraft," he said, adding, "China and Russia continue to lag behind because of the really top-end manufacturing processes you need" to create and tune high-quality aircraft engines.

So while China's new "impressive low-observable heavy strike" fighters could change the balance of power in the Pacific, whether they can field the planes in significantly large numbers at any time in the near future remains an open question.

Watch footage of the J-20's flight below: