As I am sure you know, Spaceballs features the character Pizza the Hutt, whose name seems to be obviously derived from the company Pizza Hut. Given that "Pizza Hut" is trademarked, did the filmmakers need to get approval to name the character?
A brand like Pizza Hut can be trademarked but not copyrighted. Copyrights allow the author (or owner of the copyright) to retain exclusive rights to use the work or significant portions of it. Trademarks do not work that way.
Trademarks are meant to provide legal recourse when a business uses the same or similar name, logo, design, catchphrase, etc., as another business in a way that competes with or damages the reputation of the business that holds the trademark. Words, phrases, logos, symbols, and designs can be trademarked. Like copyrights, authors of such works are protected whether or not their trademark is registered, but registration makes legal protection much easier.
The producers of Spaceballs did not have to clear the character name of Pizza the Hutt before they released the movie, but they probably did it just in case. Two likely reasons why Pizza Hut would have allowed it are:
- It did not compete with or damage their brand. The movie is not pizza or food of any kind, and while the name is funny and the character is an evil one, there is no reference at all beyond the name itself to the real world Pizza Hut. The lack of competition or damage means that Pizza Hut would have a hard time winning any legal actions they might have considered taking if the name had been used without their consent.
- Pizza the Hutt kind of looks delicious and is described as delicious by his majordomo, so the character is likely to make viewers hungry, crave pizza specifically, and have the name of Pizza Hut planted in their minds. The character is an advertisement for Pizza Hut in a way. For all we know, Pizza Hut might have even paid the producers as a kind of product placement deal (I can't find any solid evidence one way or the other).
Note that in Spaceballs there is also a Mr. Coffee coffee machine of the future that makes coffee described as "too hot" by a character, which is closer to damage (IMHO) than the character of Pizza the Hutt.
Interestingly enough, since Spaceballs is a copyrighted work, if Pizza Hut created a television advertisement showing footage of Pizza the Hutt from Spaceballs, they would have to get permission to do so from the company that owns the copyrights to the movie.
Also note that exactly what constitutes "damage" or infringement in general in a legal sense is determined in the courts, not spelled out explicitly in the law. Legal precedence set by previous court cases is usually, but not always, followed by judges, but generally legal teams prefer to clear everything before a movie is released, because going through that process is a lot less expensive than even a successful defense in a court case.
One interesting and educational example of a real-world trademark dispute is the case of Apple Corps vs. Apple Computer. The companies had the same name (more or less), but in the original case, since one company made and sold computers and the other company made and sold records, it was decided that there was no trademark infringement. But Apple Computer was specifically enjoined to not get into the music business. Of course it went back to trial a few times over the subsequent years, such as when the iTunes Music Store was created.