Simon was found dead in a kennel at O'Hare Airport in Chicago following the journey. The rabbit had been placed in a United Airlines kennel while awaiting a connecting flight to Kansas City, where his new owners were set to pick him up, CBS News reported.
The lawsuit, which was filed yesterday by a group of Iowa businessmen, seeks unspecified damages to cover the costs of the rabbit, the report said.
Simon's new owners had also planned to display him and sell related merchandise to raise money for the annual event.
According to the report, the owners said in May they were seeking the costs of buying and transporting the rabbit, an estimated USD 2,300, as well as future earnings.
The lawsuit claims the airlines was negligent in the care and transportation of the rabbit and that it improperly treated the animal. It also alleges the airline has a poor record of transporting animals, noting the airline accounted for a third of all animal deaths via US air travel in the last five years.