Autonomous flight control software is still only able to handle the simplest missions. Maybe that will change in a few years but for now anything complex requires a remote pilot, and those communication links are very vulnerable.
Wildly dependent on your definition of "modern", which mostly depends on your potential adversary. The Russia/Ukraine, and the new war in the Gulf have shown numerous ways in which 4th generation jets, and more importantly cheaper missiles and even more cheap drones can perform supression of enemy air defences and/or air support. Unless you're fighting the US or China, 4th gen jets are plenty. And even against US and US defended locations, cheap drones and missiles have been able to influct some pretty serious damage to critical infrastructure (like extremely expensive and rare radar systems). An adversary not crippled by extreme sanctions and corruption for decades might have been able to achieve even more, even with the total lack of airpower.
The real reason stealth is needed is as a counter to GBAD. Modern anti-aircraft missiles are incredible lethal.
But isn't that true of the F35 as well?
On it's own, I doubt it would survive much longer on the eastern front in Ukraine.
In Iran the F-35 also did not fly around freely while the ground radars were active. They had to be taken out first. For that stealth was probably useful (and in general it is).
But it is not making them invisible - and cheap sensors and AI is likely to counter it soon. Because sensors and analysis will get better over time and sensors also better and cheaper. But the stealth will remain largely the same. It cannot really be upgraded for existing jets.
The burning question is what decision would AI make in Pearl Harbor. Would it have said flock of birds? Would it be keying in on flocks of birds instead?
> have no choice
That's my point. Any battlefield today is "modern", but militaries operate with what they have. From Russia to the Houthis passing via the Houthis, we've seen insane amounts of damage done on "a modern battlefield" with anything from Cold War era equipment to cheap drones assembled by a terrorist group living in the mountains with no industrial base.
Yes, if the US wants to fight China, and vice versa, it needs 5th gen jets. Everyone else doesn't need them. They're nice to have to make your job easier (like Israel vs Iran), but don't guarantee you anything (like Israel vs Iran).
It's quite likely that in about 5 years most military installations will have a mix of weapons to intercept those systems - and depending on a number of factors you could easily end up back at low performance drones being so reliably intercepted as to be a waste of munitions to deploy.
WW1 after all was based on exactly this thinking: surely the volume of an army would overcome the machine gun.
That's unlikely. Anti-drone defences will only improve, yes, but autonomous drone swarms numbering in the thousands to tens of thousands are doable today, and few weapons systems can handle the rate of launch/fire required to combat that. Especially if there are follow-up waves mixing drones and heavy missiles against which your anti-drone defences wouldn't be enough.
> WW1 after all was based on exactly this thinking: surely the volume of an army would overcome the machine gun.
But building a cheap kamikaze drone costs much less than building a human.
They're now much closer to $3000 USD+ at the low end for an ISR vehicle. $8000+ for the more capable FPV kamikazes is the estimate for Russian models.
Which is comparable to a 155mm artillery shell. But with a lot less payload.
There's already literally millions of drones being produced and used per year in that conflict - and they've made a big impact, but the stability of the frontline also reveals that the impact of "swarms" is hardly overpowering (the obsession with them is also weird - if you had thousands of assets in the air, the last thing you'd do is put them all close together).
As Iran shows, you don't need overpowering. You need to hit the enemy where it hurts them, like strategic infrastructure.
> "swarms" ... (the obsession with them is also weird - if you had thousands of assets in the air, the last thing you'd do is put them all close together)
On the contrary, a swarm allows you to overwhelm the enemy air defences, which allows you to hit targets, including those same air defences, without having to disable them first. Cf. Iran destroying a THAAD radar.