Clarifying Michigan’s Unjust Enrichment Test: Direct vs. Indirect Benefits and the Inequity Requirement

Introduction

In Kelsey Trotta v. American Airlines, Inc., 25a0211n.06 (6th Cir. Apr. 18, 2025), the Sixth Circuit addressed whether a passenger-plaintiff can maintain an unjust enrichment claim against an airline that receives a share of revenues paid to a third‐party vendor. Kelsey Trotta bought travel assistance from Allianz Global Assistance (“AGA”) while booking a flight on American Airlines’ website. Only after purchase did she learn that American received a “cut” of her payment to AGA. Trotta sued on breach of contract and unjust enrichment grounds, challenging the airline’s alleged “hidden fee.” The district court dismissed both claims for failure to state a claim. On appeal, Trotta pressed only her unjust enrichment theory. The Sixth Circuit affirmed, clarifying two core elements of Michigan unjust enrichment law: (1) how “indirect” benefits may be treated and (2) the necessity of showing inequitable retention of value.

Summary of the Judgment

The Sixth Circuit affirmed dismissal of Trotta’s unjust enrichment claim. After reviewing Michigan law de novo, the court acknowledged that an unjust enrichment claim requires (1) the receipt of a benefit by the defendant and (2) an inequity resulting from the defendant’s retention of that benefit. The panel observed that American did receive money—Trotta’s travel‐assistance fee—and that it retained a portion of it. But the court found no inequity: Trotta voluntarily paid the published price for a service she fully received. Because she got exactly what she paid for (travel assistance), American’s retention of part of the fee did not offend “natural justice and equity.” Accordingly, Trotta failed to state a claim under Michigan’s unjust enrichment doctrine, and the Sixth Circuit affirmed.

Analysis

Precedents Cited

Robbins v. New Cingular Wireless PCS, LLC, 854 F.3d 315 (6th Cir. 2017) – Standard for de novo review on motions to dismiss.
Conlin v. Mortgage Electronic Registration Sys., Inc., 714 F.3d 355 (6th Cir. 2013) – Erie-doctrine guidance in diversity cases.
In re Dow Corning Corp., 419 F.3d 543 (6th Cir. 2005) – Binding effect of state supreme court decisions.
Wright v. Genesee County, 934 N.W.2d 805 (Mich. 2019) – Defines unjust enrichment and its elements under Michigan law.
Karaus v. Bank of New York Mellon, 831 N.W.2d 897 (Mich. Ct. App. 2012) – Two‐element test: benefit received and inequity from retention.
City of Highland Park v. County of Wayne, 2018 WL 1020188 (Mich. Ct. App.) – Confirmation that enrichment plus injustice are required.
Kammer Asphalt Paving Co. v. E. China Twp. Schools, 504 N.W.2d 635 (Mich. 1993) – Example of inequity when performance is received under promise of payment.
University Pediatricians v. Wilson, 2021 WL 4228193 (Mich. Ct. App.) – Voluntary transactions bar unjust enrichment claims.
AFT Michigan v. Michigan, 846 N.W.2d 583 (Mich. Ct. App. 2014) – “Entirely voluntary” nature of payment defeats restitution.
Whiteman v. AGA Service Co., 2025 WL 869409 (11th Cir.) – Parallel holding for JetBlue and Allianz arrangement: no detriment when consumer pays listed price and receives the service.
Gerboc v. ContextLogic, Inc., 867 F.3d 675 (6th Cir. 2017) – Convenience premia are lawful; profit from distribution channels is permitted.
Donoff v. Delta Air Lines, Inc., 2020 WL 1226975 (S.D. Fla.) – Airlines’ compensation for access to sales platform is self-evident and not deceptive.

Legal Reasoning

The court began by identifying Michigan’s two‐element unjust enrichment test: (1) the defendant’s receipt of a benefit and (2) an inequity resulting from retention of that benefit. Although Trotta and American Airlines disputed whether Michigan requires a direct benefit from plaintiff to defendant, the Sixth Circuit bypassed that issue. It found the case dispositive on the second element: inequitable retention.

Under Michigan law, retention is inequitable only when a plaintiff is deprived of the value she was promised or receives no benefit despite payment. Trotta paid $X for travel assistance and received full access to concierge, medical referrals, translation, and other services. The airline’s receipt of a commission did not diminish her service. Nor was there any deception: American’s booking path clearly noted that AGA, not the airline, “recommended/offered/sold” the product, and it displayed the checkout price. Thus, no “hidden fee” induced purchase by mistake or coercion.

The court rejected analogies to “something for nothing” because American provided the integrated booking convenience: the airline’s digital platform saved Trotta the trouble of navigating to AGA’s site. Justice and equity do not forbid compensation for convenience or distribution access, just as stadium concessions charge a premium for on-site sales.

Impact

This decision sharpens the boundaries of unjust enrichment claims in Michigan and federal diversity courts:

It underscores that a plaintiff who receives precisely the services paid for cannot claim inequity simply because a third party remits a commission to the defendant.
It diminishes the viability of class actions attacking airline distribution-fee arrangements absent evidence of deception or shortfall in promised goods or services.
It suggests that future plaintiffs must focus on false statements, regulatory noncompliance, or actual service deficiencies, rather than on revenue-sharing structures alone.
It affirms that convenience and bundled offering premiums are permissible under equity principles.

Complex Concepts Simplified

Unjust Enrichment: A legal theory requiring a defendant to repay money retained unfairly at another’s expense.
Benefit & Inequity Elements: (1) The defendant must receive something of value; (2) it must be unjust or unfair for the defendant to keep it without paying its value.
Direct vs. Indirect Benefit: Whether the plaintiff must have paid the defendant directly; unresolved here because the inequity element proved dispositive.
Erie Guess: A term meaning a federal court must predict how a state’s highest court would decide a new question under state law.
De Novo Review: The appeals court reconsiders legal conclusions from the district court without deference.

Conclusion

Kelsey Trotta v. American Airlines, Inc. crystallizes Michigan’s unjust enrichment requirements in third‐party revenue contexts. Even if a defendant pockets a share of a consumer’s payment to a vendor, liability attaches only if the consumer did not receive the full benefit paid for or was misled into payment. Integrated convenience offerings—wherein airlines bundle third‐party services at advertised prices—do not give rise to restitution claims simply because a commission is involved. This ruling thus narrows the scope of unjust enrichment in consumer and class actions, steering litigants toward claims rooted in deception or statutory violation rather than mere fee‐splitting arrangements.