In the 1991 case of Walter Lee, Superintendent of Port Authority Police v. International Society for Krishna Consciousness, Inc., et al., the U.S. Supreme Court ruled on whether or not airports were considered public forums where religious solicitation could occur freely under First Amendment rights. The International Society for Krishna Consciousness (ISKCON) had challenged a regulation by the Port Authority of New York and New Jersey that prohibited distribution of literature and solicitations within airport terminals without permission from authorities. ISKCON argued this violated their freedom to exercise religion and speech as protected by the First Amendment. The court held in a 6-3 decision that airport terminals operated by governmental bodies are not public forums because they are not traditionally devoted to assembly and debate like streets or parks would be; therefore, restrictions can be placed on expressive activity such as distributing literature or soliciting funds if it is reasonable and viewpoint-neutral. However, they also noted that while an outright ban might be too broad, regulations must leave open ample alternative channels for communication.

In the dissenting opinion for Walter Lee v. International Society for Krishna Consciousness, Inc., Justice Clarence Thomas argued that airports should be considered nonpublic forums because they are not traditionally used for public communication and assembly. He contended that the majority's decision to classify them as limited public forums was incorrect and could potentially open up all government property to First Amendment activity, regardless of its compatibility with the intended use of the property. Furthermore, he believed that even if airports were classified as limited public forums, restrictions on solicitation would still be reasonable due to concerns about congestion and fraud. Therefore, in his view, Port Authority’s ban on solicitation was justified.