It is unclear whether Trump has the legal authority to decertify aircraft; the White House has not released an executive order on any Canadian aircraft tariffs. In addition to business jets, Bombardier makes the CRJ regional jets used on feeder flights, which typically take passengers from smaller airports to larger airports. United, Delta and American airlines all employ regional airlines that use CRJ on their feeder flights. There are 648 passenger CRJ jets that were made in Canada that are in use by US airlines, according to aviation analytics firm Cirium. Regional airlines are the only source of flights for 64% of US airports, according to the Regional Airline Association’s data.