That's indeed correct. The Civil Rights Act of 1964 provides that service cannot be refused* on the "ground of race, color, religion, sex, or national origin", other than that it is really fair game.
In fact it is a right for businesses to choose who they want to serve. An airline that only flies costumed clients? 100% a right in this country. They can even decide who they consider costumed and who not.
* In research I discovered that it depends actually on the type of service. In California the Unruh Civil Rights Act catches all businesses; but federally only certain types of businesses must follow the discrimination rules. http://users.wfu.edu/zulick/341/civilrightsact1964.html
Airports are included in the Civil Rights Act because "it serves or offers to serve interstate travelers".
Note that in California the Unruh Act more or less states that businesses do not have a right to refuse service for anything not related to the business transaction. For example, the ACLU was successfully sued under the law for kicking off-duty police officers out of a seminar on police surveillance, and banks have been sued for denying loans to homeowners who expressed interests in running home-based day care centers.
In fact it is a right for businesses to choose who they want to serve. An airline that only flies costumed clients? 100% a right in this country. They can even decide who they consider costumed and who not.
* In research I discovered that it depends actually on the type of service. In California the Unruh Civil Rights Act catches all businesses; but federally only certain types of businesses must follow the discrimination rules. http://users.wfu.edu/zulick/341/civilrightsact1964.html
Airports are included in the Civil Rights Act because "it serves or offers to serve interstate travelers".