In the case of Aero Mayflower Transit Co. v. Board of Railroad Commissioners of Montana et al., 1947, the U.S Supreme Court ruled in favor of Aero Mayflower Transit Company, a moving company that operated across state lines. The State Board had attempted to regulate and impose fees on the company's operations within Montana, arguing that it was acting as a public utility under state law. However, the court found this regulation unconstitutional due to its interference with interstate commerce which is protected by federal law under Commerce Clause powers granted by Article I Section 8 Clause 3 of US Constitution. Therefore, states cannot interfere or regulate companies operating across multiple states; such matters fall under federal jurisdiction.

In the dissenting opinion for Aero Mayflower Transit Co. v. Board of Railroad Commissioners of Montana, Justice Frank Murphy argued that the majority's decision to allow states to regulate interstate commerce was a departure from established constitutional principles and could potentially lead to economic chaos. He contended that only Congress has the power to regulate interstate commerce under the Commerce Clause of the Constitution, not individual states. By allowing each state to impose its own regulations on businesses operating across state lines, he feared it would create an untenable situation where companies are subject to conflicting rules in different jurisdictions. This could hinder free trade between states and disrupt national unity by fostering provincialism at expense of national interests.