Plaintiffs in consumer class action lawsuits often assert a theory of harm based on an alleged overpayment. The typical claim is that a plaintiff bought a good or service that had some alleged defect or was subject to some misrepresentation, and that they therefore paid more than they would have absent the defect or misrepresentation. While that may be enough to establish Article III standing in some cases, the Fifth Circuit recently reaffirmed that the theory has limits.

In Monahan v. Southwest Airlines Co., 2026 WL 1035070 (5th Cir. Apr. 16, 2026), airline ticket purchasers brought a class action alleging that Southwest had breached the terms of their purchase agreements. The theory? Southwest operated MAX 8s in its fleet before the FAA temporarily grounded the plane. Plaintiffs claimed that the MAX 8s were unsafe and that, because Southwest promised to operate safe aircraft, they had overpaid for their tickets. That was so, plaintiffs alleged, despite their concession that they had never flown on a MAX 8. Instead, they alleged that the mere fact that Southwest could have placed them on a MAX 8 caused them to suffer economic injury because it made their tickets less valuable.

The Fifth Circuit rejected this theory. The court noted that plaintiffs’ claims rested on the idea that Southwest’s conduct allowed the airline to overcharge its customers for plane tickets. But that relied on a mistaken and implausible theory of overpayment. If anything, plaintiffs were better off financially, because had Southwest known about any defects, it would have likely offered no flights on MAX 8 planes—leading to the MAX 8 being taken off routes, a decrease in the number of planes, and a likely increase in ticket prices. The court held that there were no plausible allegations that the airline would have reduced its prices had it known about any risks, and therefore plaintiffs had failed to plead an injury sufficient to establish standing.

Monahan reaffirms that merely invoking “overpayment” does not establish an injury for Article III purposes. While overpayment is a viable way of establishing an economic injury—and therefore standing—the theory of economic injury still needs to be plausible.