Some history. Remember, Six Flag was owned by Time-Warner, but Six Flags couldn't use Time-Warner's Looney Tunes characters because competitor Great America theme parks owned them. So, what did they do? They bought the entire franchise of Great America theme parks and merged it with Six Flags! Thus, because of this move, Six Flags then had the theme park rights for Looney Tunes (as well as the Great America parks which became Six Flags parks). That would be like the equivant of Disney buying Universal's parks, which I am not even remotely suggesting! From Wikipedia:
"In 1976, the Looney Tunes characters made their way into the amusement business when they became the mascots for the two Marriott's Great America theme parks (Gurnee, Santa Clara). After the Gurnee park was sold to Six Flags, they also claimed the rights to use the characters at the other Six Flags parks, which they continue to do presently."