What is the airport code for Omaha, Nebraska?

The airport code for Omaha, Nebraska, is OMA. This code is used internationally to identify Omaha's Eppley Airfield, which serves as the primary airport for the city. Airport codes typically consist of three letters and are often derived from the name of the city or nearby geographical features. In this instance, OMA is a straightforward abbreviation using the first two letters of "Omaha" along with an additional letter to ensure uniqueness among other airport codes.

The other options represent different airports: ONT is for Ontario International Airport in California, SNA refers to John Wayne Airport in Orange County, California, and MCO is the airport code for Orlando International Airport in Florida. These codes do not correspond to Omaha, clarifying that D is indeed the correct choice.