The Globe and Mail reports in its Saturday edition that U.S. President Donald Trump's declaration that he has decertified new Canadian aircraft in the United States has spurred accusations the President is undermining safety functions of regulators. The Globe's Eric Atkins writes Mr. Trump made the announcement on Thursday night on social media, along with a warning he would slap 50-per-cent import taxes on planes made by Bombardier and other Canadian manufacturers. Canadian aviation regulators are reviewing changes to U.S.-made Gulfstream business jets. Where appropriate, aviation authorities certify aircraft for safety reasons, including updates or changes to existing models. Canada is reviewing electronics changes to Gulfstream G700 and G800 models the company made to increase its range and payload, said John Gradek, who teaches aviation leadership at McGill University. Mr. Gradek said Gulfstream is upset Bombardier is outselling it in the U.S., and unhappy with delays obtaining Canadian certification of recent updates. "This is a trade war between Gulfstream and Bombardier," he told The Globe. Rather than lose the sales battle, Gulfstream pressured Mr. Trump to ban Bombardier's planes from the United States.