[asperous]

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".

[einhverfr]

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.