In a post on his Truth Social platform, Donald Trump announced that all Canadian-made aircraft will be decertified.The American president says that this is as a result of Canada apparently refusing to certify the American-built Gulfstream 500, 600, 700, and 800 class of jets."Based on the fact that Canada has wrongfully, illegally, and steadfastly refused to certify the Gulfstream 500, 600, 700, and 800 jets, one of the greatest and most technologically advanced airplanes ever made, we are hereby decertifying their Bombardier Global Expresses and all aircraft made in Canada," wrote the American president on Thursday.The dispute with Canada seems to be over regulatory issues, which sit more with Canadian aircraft regulators than the government..In retaliation, Trump not only announced that all Canadian-made aircraft are to be decertified in the United States but also took a specific shot at the Canadian-built Bombardier Global Express.He then wrote that if the situation wasn't corrected, a 50% tariff would be implemented on all Canadian aircraft sold in the United States.This seems to be oxymoronic with his previous statement, as if Canadian aircraft are decertified, they wouldn't be able to be sold in the United States anyways, making the tariff irrelevant.This is yet another in an ongoing list of threats and warnings from the American president to Canada in the ongoing Canada-US trade war.