I refuse to believe that if Lucas was really that interested in putting in other aliens he couldn't have at least put one alien mask on somebody in the rebel briefing in ANH or on some rebel in Hoth. The total lack of aliens there, in films that had the cantina and the ugnauts, really stands out and I don't think it's just down to budget.

xhonzi said:

It seems they could have put a few masks in the Yain briefing scene (re-use ones from the cantina) if they wanted some alien presence.

Exactly.

It strikes me that Lucas wasn't too concerned with portraying the rebels as anything but humans. And that fits with the way they were overwhelmingly portrayed as male and white as well, in the first two films. In ROTJ, there are female rebels of significance (they're led by a woman, which is a big difference from having one female radio operator), non-white rebels (such as among the pilots) and alien rebels. It's clear the change was a change in the attitudes of the day, not a change in budget or special effects capabilities.

Gaffer Tape said:

Yeah, it seemed that George always wanted to put more and more different races in the films,

Where do you get this info from?

Wanting to put in more different races in the films doesn't necessarily mean putting in more in the rebellion. It could mean putting more in the cantina or in Bespin or on the streets of Mos Eisley.