But interestingly their ambitions are "local". This has a large impact on the machines and materials required.
In other words, let's says the Chinese military jet engine is 15 years behind is say fuel economy. Which reduces range. If the conflict is local that doesn't matter overmuch.
Equally operating from land, not carriers, reduces reach, but if what you want to reach is local then that doesn't matter.
If China has military ambitions (and despite the sabre rattling there's no overt indication of that), they are all in a specific area.
By contrast the US likes to participate in, or instigate, actions far from home. Moving planes means long open-ocean ferry flights. Single-engine reliability, range, effeciency and so on is paramout.
Equally the US relies on friendly local countries to provide support bases, logistics, fuel and so on. As evidenced just this year, that support can be withdrawn. Will Japan or Korea want to be dragged into a US / China conflict over Taiwan?
So if the Chinese are operating engines later than the first gulf War, and on par with the second, I'm not sure that's a defining difference.
The US doctrine of air-defence suppression followed by air superiority may not be possible in a space near the Chinese mainland.
In a military context, the main technological gaps relating to jet engines are supercruise and maintenance hours. Both are potentially quite relevant in a ‘local’ conflict.
I'm not sure about maintenance hours. That matters as a function of proximity to maintenance staff, parts, new supply and so on. Flying from home bases, with no shortage of skilled labor can cover that.
Supercruise also matters a bit less when the distance to combat is shorter. Less fuel expended on "getting there" is more fuel for "on station". Plus, assuming more-or-less unlimited supply of machines and pilots means more flight hours on station.
So while the engines play a part in a hypothetical conflict, supply lines (and the length thereof) play (I think) a larger part.
Supercruise matters directly for BVR combat. It means that you can get high and fast to launch your missiles with the best parameters without burning half your fuel via afterburners. (Many fighter jets would burn through all their fuel in under 10 minutes at full afterburner.)
Maintenance hours are sure to matter in a real war where equipment is getting destroyed and supply lines are being disrupted.
I think you vastly underestimate how maintenance requirements impact how rapidly you can bring forces to the fight and how long you can keep them there. While that is exacerbated by long supply lines, it is an extremely important factor in any combat scenario.
The F-35, which was optimized for congressional district employment, has an effective 25% readiness rate (another 25% can fly but not fight), which is half of the 40 year old F-15C and 1/3 the newer F-15s.
In other words, let's says the Chinese military jet engine is 15 years behind is say fuel economy. Which reduces range. If the conflict is local that doesn't matter overmuch.
Equally operating from land, not carriers, reduces reach, but if what you want to reach is local then that doesn't matter.
If China has military ambitions (and despite the sabre rattling there's no overt indication of that), they are all in a specific area.
By contrast the US likes to participate in, or instigate, actions far from home. Moving planes means long open-ocean ferry flights. Single-engine reliability, range, effeciency and so on is paramout.
Equally the US relies on friendly local countries to provide support bases, logistics, fuel and so on. As evidenced just this year, that support can be withdrawn. Will Japan or Korea want to be dragged into a US / China conflict over Taiwan?
So if the Chinese are operating engines later than the first gulf War, and on par with the second, I'm not sure that's a defining difference.
The US doctrine of air-defence suppression followed by air superiority may not be possible in a space near the Chinese mainland.