My spouse and I went to see this on opening night. We were expecting to see an extremely bad and costly film, and we were not really disappointed. It is a testament to John Travolta's genius that his career survived this disaster at all.
As they say, garbage-in, garbage out. Start with an L Ron Hubbard novel (your first mistake) featuring a completely plagiarized dark-skinned, war-like and hairy alien culture with wrinkly foreheads (if this sounds like Klingons to you, I thought so too!), and add unfortunate Barry "can't get a break" (or maybe it should be 'cant pick a script') Pepper and all you need is Travolta himself - playing the arrogant, merciless, slightly effeminate and quite under-sized leader of the alien colonists. Remove any hint of character development from the script and use the worst of the worst black box technobabble explanations for plot devices. Finally, stay true to the idiotic gibberish you based the film on in the first place, and you've got the makings of a rolling-on-the-floor comedy.
In fact, opening night, in a packed theater, people started laughing out loud about 20 minutes into the film and never really stopped. We had a great time that night. Halfway through the film more than half the crowd was actually interacting with the film, asking "Mr Worf, where's Commander Riker?" and asking troublesome questions about how many hundreds of years gas would remain viable in the gas-tank of a Harrier.
If you need to know about the plot - it's this simple - Earth has been conquered by an amazingly stupid group of Klingon-like aliens, and the remaining humans live in a large domed slave labor camp where they are taught that their sole purpose is servitude because they are stupid, weak, etc. Barry Pepper somehow becomes convinced that he's not born to be a slave, and learns to fly a harrier, etc. It's really not worth the effort of typing. There are a few not-so-subtle and not very original but good messages about ethnocentrism to be found here, but not much else. Some day when you need a good laugh, rent this or borrow it from your local bad film collector.