Looking at that alien on the right (is he wearing a monocle?) someone had obviously been watching too much Doctor Who: http://en.wikipedia.org/wiki/Zygon
Spotted that myself, then I thought 'let Zygons be Zygons'...
the spaceship is definitely early O'Neill I reckon
The USA type certainly looks like his.
A paste-up job maybe? Kevin O'Neil worked in the 2000AD offices as an art director(?) at the time. Maybe Goring's spaceship illustration wasn't sexy enough?
Your comments are very welcome!