Omaha, Nebraska is 3% larger than Kansas City, Kansas.
Area: 332 km2 calculated
Kansas City is the third-largest city in the state of Kansas, the county seat of Wyandotte County, and the third-largest city of the Kansas City metropolitan area. It is part of a consolidated city-county government known as the "Unified Government". Wikipedia
Area: 342 km2 calculated
Omaha is the largest city in the state of Nebraska, United States, and is the county seat of Douglas County. It is located in the Midwestern United States on the Missouri River, about 10 miles north of the mouth of the Platte River. Wikipedia