When I visited OMA, I was surprised that all the rental car offices were on the approach road just across the Missouri River in Council Bluffs IA. The hotel shuttle driver said that's because Nebraska has a will tax on vehicle registrations, so the rental companies prefer to register the car in Iowa. He also pointed out the older cars parked in front of people's houses and in driveways with MO plates. His explanation was that some clever locals have avoided the will tax by setting up "primary residence" in Missouri, which apparently has lenient residency requirements.