Spaceballs/WMG

Druidia was not the first planet that got preyed upon by the Spaceballs.
The main clue to this theory is the Druidian air shield. Why would a planet install such a cost-intensive device if there weren't already some known cases of "air theft" in the galaxy? It may be that other races than the Spaceballs also prey on planets for their air, but it might as well be possible that the Spaceballs themselves didn't do it for the first time. Or both.
 * The Spaceballs reputation for air-theft is noted in the opening text crawl.
 * Besides, they're Druish. They wouldn't let a single molecule of air escape if they had a way to keep it around.

Spaceballs The Animated Series was an evil plot by the Spaceballs.
They plotted, quite brilliantly, to destroy all good faith in the movie, thus disrupting all future attempts at a sequel or merchandising, thus depriving Yogurt of his source of income and leaving him weakened for the coming battle!
 * Of course! On a more serious note, though, Mel Brooks ruled out all possibilities of a sequel when John Candy died.

Lone Starr is the "canonical" mind-wiped Revan.

 * Hey, Rino Romano is the voice for both Revan in KOTOR, and Lone Starr (in the animated series).
 * They both learned how to the the Force (or "da Schwartz") with minimal training.
 * One of the classes you can play in KOTOR is a Scoundrel.
 * Lone Starr doesn't seem to know anything about his past. Plausible enough to make it a lie.
 * If Vespa and Bastila find one another, that's gonna be the mother of all catfights.
 * Wait, Revan has lines? (Yes, the lines he says when he picks locks, sets mines, etc.)

Lone Starr and Helmet are former roommates.
I Am Your Father's Brother's (Lone Starr's Uncle) Nephew's (Lone Starr's Cousin) Cousin's (Lone Starr) Former Roommate.
 * The reason Helmet hates Lone Starr so much was because whenever Lone Starr used up all the jam, he would invariably replace it with strawberry.
 * Raspberry. Because only one man would dare give him the raspberry.
 * Or he could be Lone Starr's cousin's former roommate and hates Lone Starr because of something involving raspberries that happened at a party.
 * Actually, "father's brother's nephew" brings it back to Lone Starr. Then add "cousin", making it Lone Starr's (probably first) cousin. Then "former roommate" would be brother (if during childhood) or Total Stranger (if in adulthood). The latter is most likely ("What does that make us? Absolutely nothing!). However that still means Dark Helmet not only knew Lone Starr's cousin, but that that person WAS Lone Starr's cousin. On the other hand, Evil Lies ("You said you'd let her go!" "I lied."), and he could have just been making the whole thing up. (And, to make things worse, if he was telling the truth, he never said the cousin was male. It could have been Princess Vespa. Which makes Dark Helmet's infatuation with her not as sudden as it seemed, and, yes, Princess Vespa marries her cousin, which was common practice in Medieval Europe in order to keep money and power in the family, and could be a joke of itself.)
 * No, it could be Lone Starr himself, if the nephew is by his father's other brother or sister.

Lone Starr is the Rightful Heir to the Kingdom of Spaceball.

 * When the villainous President Skroob seized power, his Dragon Dark Helmet (who was a member of the Royal Entourage due to being etc-etc-roommate) killed the Royal Family. But the Royal Family's faithful Mawg retainers spirited the Infant Prince away to a monastery. This explains why Dark Helmet hunted Lone Starr before the movie (he knew that Lone Starr was the Lost Prince, due to the family resemblance and him having a Mawg retainer).

Lone Starr's name is actually an alias.
The last name Starr isn't that awkward, but naming someone Lone? It's got to be a pseudonym
 * Or his parents assumed he'd become a loner who drifts from space port to space port with only his ship and his furry friend and gave him a name to suit it (hoping to god that he didn't enter an occupation that involves extensive socializing).

The fragments of Spaceball One is the Statue of Liberty arm found in Planet of the Apes.
That means it's not a future Earth. It still is literally another planet.

One of Lone Starr's parents are distant relatives to King Roland.
How else would they be a king and queen?
 * Um, they're from another planet? Or maybe just another country?

Dark Helmet murdered Lone Starr's parents.
Think about it. Why would his parents, who were royalty, abandon him in the care of a group of monks? Something bad must have been after them. And we know that Helmet knew Lone Starr's family, since he was his father's brother's nephew's cousin's former roommate. At some point, Helmet turned to the Down Side of the Schwartz and betrayed and murdered the Starrs.

Dark Helmet assassinated all the other princes in the Galaxy.
Their entire plan seemed to hinge on Vespa pulling a runner at the altar-- what better way to ensure this than by making sure her other option was the most odious potential husband ever? By leaving Valium the only prince left, they could ensure that Vespa would flee the planet.
 * His line "I hope its a long ceremony, cuz its gonna be a short honeymoon" has a whole new meaning.

Pizza the Hutt is a Pizza Elemental
You can find one as an easter egg, and, predictably, it is enormously difficult. Pizza the Hutt is very feared for perhaps this reason.

The radar technician (played by Michael Winslow) is the only non-Asshole.
He's that one who didn't raise his hand when Helmet asked who's an Asshole in the ship. Just because.

Vespa's mother was assassinated.
She was dead by the time Vespa was getting married. Though its never explained how she died or when, its possible she was killed (possibly by a Spaceball spy or assassin). They may have used a gun. This explains why Vespa Doesn't Like Guns. Which adds to the ironic humor that she used a gun because a Spaceball trooper shot her hair. The one who shot her hair may even be her mother's killer.