The investment comes at a shaky moment for travel between Canada and the U.S., with Canadians taking fewer trips to the U.S.

Delta Air Lines (NYSE:DAL) and Korean Air announced on Friday that they will strengthen their respective partnerships with WestJet through the purchase of minority equity stakes in the Canadian airline from Onex Partners.

Delta will invest $330 million for a 15% stake and Korean Air will inject $220 million for a 10% interest. The U.S. airline also plans to sell and transfer a 2.3% stake in WestJet to its joint venture partner, Air France-KLM, for $50 million.