All-American Flag Act (Sec. 2) This bill prohibits agencies from using funds to procure a U.S. flag unless such flag has been 100% manufactured in the United States from materials that have been grown or 100% U.S. produced or manufactured. This prohibition does not apply if an agency determines that satisfactory quality and sufficient quantity of U.S. flags cannot be procured as needed at U.S. market prices. Nor shall such prohibition apply to procurements: by vessels in foreign waters; for resale purposes in any military commissary, military exchange, or non-appropriated fund instrumentality operated by an agency; or for amounts less than the simplified acquisition threshold. The President: (1) may waive the prohibition upon determining that a waiver is necessary to comply with a trade agreement, and (2) shall publish a notice in the Federal Register within 30 days of granting a waiver.