Jeannie knows that the killer bees are attracted by red objects, but she keeps using her red car, even when she starts to search for the swarm with Dr. Mueller. Dr. Mueller's plan to fight the bees fails, and they attack the car. The filmmakers probably introduced this character error because the color of the car comes in handy for plan B, which involves taking the bees to the Superdome. Since they cling to her car, Jeannie can take them there by simply driving (slowly) to the Superdome.