Are the Xenomorphs intelligent enough to commandeer a spacecraft they overwhelm, or do they just go along for the ride?
No. The rolling, flaming destruction of the commandeered dropship in Aliens demonstrated poor piloting skills at best and a complete lack of situational awareness at worst. If the alien were intelligent it would have waited until the dropship landed safely before turning both pilots into salsa.
I would have to say "no", they are not intelligent enough to control/pilot a ship. They are shown to have some degree of intelligence when they interact with basic machinery, for example:
- The Queen figuring out how to use an elevator in Aliens.
- A xenomorph pushing a button to blast someone with gas in Alien: Resurrection.
But these interactions are tantamount to simply pushing a button. So, if they ever commandeered the Heart of Gold, well, we're all in trouble:
I would have to say, "yes" or at least we do not know. I think that one comic or novelization indicates that queens can be more intelligent than most humans.
But the incredible flexibility of alien reproduction, the fact that the Ripley clone retains memories of the original, implies to me that basically all bets are off and an alien who not only can speak English but can pilot a ship or even manage to overcome its genetic urges to reproduce could show up in some future version (if it has not already happened in a comic, etc.)
I say eventually they would be able to pilot spacecraft. Each new generation of Xenos is smarter than the last so in the far future they would probably have evolved enough to be able to pilot or even build spacecraft, possibly weapons too and with enough time they would be on par with the Yaut'ja. Its really simple guys. they just need to evolve more just as the Humans did.