DES MOINES, IOWA — The owners of a giant rabbit that died after flying with United Airlines are demanding an investigation into his death and compensation from the trouble-hit carrier.

Simon, a Continental Giant Rabbit, died last month after a flight from London to Chicago’s O’Hare International Airport.

The bunny’s former owner said he had a check-up just three hours before hopping on the plane and was “fit as a fiddle”.

Simon was on his way to his new owners — Iowa-based investors who had pinned their hopes on him winning their state fair’s biggest rabbit competition.

According to at least one airline employee, Simon may have accidentally been locked in a freezer for up to 16 hours after the plane landed in Chicago, the Des Moines Register reported.

Now attorneys for the rabbit’s owners are calling for an independent investigation. They say United cremated Simon after his death without permission from the owners, pretty much destroying any evidence left in the case.

Standing 3-foot-tall before his untimely passing, Simon was expected to be officially named the biggest rabbit in the world.

The Iowa group bought him from UK-based rabbit breeder Annette Edwards. She owns Simon’s four-foot-long father Darius, and he remains the world’s largest bunny.

Simon’s owners want United to pay his purchase price, shipping costs and the “economic loss” of his death. The owners are giving the airline seven days to respond before they file a lawsuit.