It was supposed to be a kids show.
I've been trying to scrounge up every morsel of info I can on Operation: Aliens for some time now, and this is the closest thing to the story that I've been able to piece together (Some gaps filled in with educated guesses):
The idea came out of the fox brain trust around the same time as the glut of marketing for Alien 3 to do Aliens as a Saturday morning cartoon show. It evidently started production through a Korean studio, but nothing is known about who exactly was involved or whether or not the alleged pilot episode was ever actually filmed. The production stills that have been posted earlier in this thread came from 'a long gone website about animation produced in Korea' but as far as I know, no video has been found.
Of course, Fox had already planned the toy line and various paraphernalia for the show. I've heard (and it seems like a logical conclusion) that the Kenner line that everyone is so familiar with was originally going to be under the Operation: Aliens brand name, but that the name was changed at the last minute since the show's production had been cancelled. It was evidently too late to change the name, though, for the Jigsaw puzzles, plaster molding set, board game, toy case, watch, and a few other items.
That's what I know. Any further information would be greatly appreciated.