Maybe they don't trust an android's programming with their hugely expensive cargo?
Can't be that - they trust the ship's AI with their hugely expensive cargo while the crew is in hypersleep.
Maybe humans have a certain adaptability that the Davids, through to the 120 A-2, lacked?
Could be, but why would you need that adaptability when you're just transporting cargo along interstellar shipping lanes? And Ash was pretty adaptable anyway - at least, none of us noticed that he was performing at less than the crew's baseline in Alien
given the restrictions he was working with. Well, he did go a bit mental at the end...
I had previously thought, in the context of Alien
anyway, that that was the reason why the Nostromo
was crewed. If something went wrong on board, you had engineers to fix it and a command line structure to make decisions. But there's no reason you wouldn't have android engineers now, and there's not much reason not to employ just a single human to make those decisions and crew the rest up with droids, as Darkfox
Tax breaks for employing real people over artificial ones?
I like that idea, but it would have had to have come in between the Weyland timeline and Alien
, otherwise Weyland's kissing goodbye to 8 million employee's tax breaks due to hiring droids.
No droids in Hadley's were mentioned either. Odd, considering the use of replicants in Blade Runner
as primarily offworld slaves for the colonists.