<h1>U.S. aircraft tariffs threatened against Canada after certification dispute, including potential 50% duty and decertification measures.</h1> A sovereign executive announced threatened imposition of a 50 percent import tariff on aircraft sold into the United States and threatened decertification of foreign aircraft following a certification dispute, constituting a trade retaliation measure tied to alleged refusal to certify U.S.-made jets. The announcement signals potential use of import tariff measures and aviation decertification as instruments to restrict market access and retaliate in bilateral commercial disputes, with the operative legal effect being prospective trade sanctions on aircraft imports and administrative withdrawal of airworthiness recognition unless the certification issue is resolved.