In the case of Dan Morales, Attorney General of Texas v. Trans World Airlines, Inc., et al., 1991, the U.S. Supreme Court ruled in favor of Trans World Airlines (TWA). The dispute centered around whether federal airline deregulation legislation preempted a Texas law that required airlines to pay out certain refunds within 45 days. TWA had been sued by the state for allegedly violating this law. However, TWA argued that they were not subject to it due to the Airline Deregulation Act which aimed at limiting states' ability to regulate airlines and encouraging competitive market forces within commercial aviation industry. The court held that under this act's preemption clause - which prohibited states from enforcing any laws related to "price, route or service" - Texas could not enforce its refund regulation against TWA as it was indeed related directly with 'price'. This decision reaffirmed federal supremacy over state regulations when there is an explicit intent by Congress for such preemption.

In the dissenting opinion for DAN MORALES, ATTORNEY GENERAL OF TEXAS v. TRANS WORLD AIRLINES, INC., et al., Justice Scalia argued that the Airline Deregulation Act (ADA) did not preempt state laws regarding deceptive advertising practices by airlines. He contended that while the ADA was intended to prevent states from interfering with airline rates and routes, it did not necessarily extend to preventing them from regulating other aspects of airline business such as advertising. In his view, allowing states to enforce their own consumer protection laws would not undermine federal deregulation efforts but rather complement them by ensuring fair competition among airlines. He also criticized the majority's interpretation of "services" in relation to air travel as overly broad and inconsistent with previous court rulings on similar matters.