498 U.S. 517 (1991), Supreme Court of the United States
Air Courier Conference v. American Postal Workers Union is a leading Supreme Court decision on the zone-of-interests test that governs who may sue under the Administrative Procedure Act (APA).
Whether the American Postal Workers Union, asserting loss of postal employment opportunities due to a USPS suspension of the Private Express Statutes for international remail, falls within the zone of interests of the relevant statute so as to have prudential standing to sue under the Administrative Procedure Act.
Under the Administrative Procedure Act, a plaintiff must be "adversely affected or aggrieved by agency action within the meaning of a relevant statute." To satisfy this, the plaintiff's interests must be arguably within the zone of interests protected or regulated by the particular statute that the agency is claimed to have violated. The zone-of-interests test is not especially demanding, but it does exclude plaintiffs whose interests are only marginally related to or inconsistent with the purposes of the statute. The relevant statute is the specific statutory provision under which the agency acted or allegedly violated, not the agency's organic act in general or broad policy statements untethered to that provision.
No. The postal workers' union is not within the zone of interests of the Private Express Statutes, which are designed to protect the public's interest in a reliable postal system and the government's postal revenues, not to safeguard postal employees' job security. Accordingly, the union lacks prudential standing to challenge the USPS suspension under the APA.
Air Courier Conference is a key case for administrative law students studying standing under the APA. It underscores that the zone-of-interests inquiry focuses tightly on the specific statute the agency is alleged to have violated, not the agency's organic act writ large or broad policy declarations. The decision narrows who may sue by excluding plaintiffs whose interests are merely incidental to a statute's aims. It also serves as a doctrinal bridge between Data Processing and later cases like National Credit Union Administration v. First National Bank & Trust Co. and Lexmark International, Inc. v. Static Control Components, Inc. Although Lexmark rejected the label "prudential standing," Air Courier's core teaching—that a plaintiff must be within the statute's zone of interests to invoke a statutory cause of action—remains foundational. Practically, the case warns advocacy groups and unions that even concrete economic harms will not suffice under the APA unless those harms align with the protective or regulatory purposes of the specific statute invoked.