I'd modify that somewhat. UCAV's certainly have a big future; they offer new capabilities (e.g. swarms of thousands, long loiter times, the ability to switch "pilots" in mid-air, the potential for radical manueverability, etc.)...but the old tools still have value, too.
Stealth UCAV's are going to be going up against American, Israeli, Russian, and Indian optical anti-aircraft missiles, for instance. What a computer can see, can be hit by a missile...if that "target" isn't too fast, too manueverable, or too high (e.g. sub-orbital).
UCAV wars get away from China's (India's too) manpower advantage, so this new trend is definitely go to cause some intriguing discussions in Beijing.
Likewise, now that American *civilians* are putting themselves into Space (e.g. Burt Rutan), the world's militaries have to start factoring in sub-orbital (perhaps even orbital) combat.
So stealth meets the optical anti-aircraft missile...and fighters/UCAV's have to cope with strike from sub-orbital or orbital platforms from high above, too.
Which is to say that aerial warfare is at one of those periodic high-change times. Manned fighters still have some value. UCAV's have some value. Optical anti-aircraft missiles have value. Sub-orbital weapons platforms have value.
The opportunity for new aerial tactics and wildly different types of air wars now abounds.
...And lets not forget that the U.S. is already fielding ground-based as well as air-borne anti-missile lasers, too.
So we're going through a rapid, hyper-fast "evolution" in potential aerial warfare right now.
You might see swarms of UCAV's, swarms in the thousands, attacking one target from multiple points on the compass, while the target itself is defended by air-borne lasers, manned stealth fighters, orbital weapons, and optically (computer) guided air-to-air missiles, for instance.
Hyper-warfare is going to ratchet up a notch, with the U.S. adding yet another length to our lead in this horse race.
I'm reminded of that time right after WW2 when some press-types were interviewing a German rocket scientist about their great progress in rockets but lousy luck in atomic weapons. One American scientist asked the German "where were your cyclotrons?" To which the German responded "we didn't have any" as he hung his head low.
They didn't have any.
Many, many nations could find out the hard way that they don't have the new technology needed to even be remotely competitive with the U.S. all over again. Not everyone has today's "cyclotrons," after all, and it's too late to go get such technology once the war is over.