Delta Air Lines and Korean Air are acquiring a combined 25% stake in Canadian airline WestJet for $550 million from investment fund Onex. Delta will invest $330 million for 15%, while Korean Air will invest $220 million for 10%.

The deal will strengthen both airlines’ positions in the North American market. Delta will also sell a 2.3% stake in WestJet to its alliance partner Air France-KLM for $50 million.

WestJet will remain under Onex control despite the new shareholders. The companies have been cooperating since 2011.

Mergers and strategic alliances between carriers are becoming more common: they help control routes, strengthen loyalty programs, and compete with larger players. However, this has raised concerns among consumers and antitrust authorities due to the potential for higher prices and reduced competition.

The deal comes as the number of flights to the United States from Canada has declined following the introduction of tariffs by President Trump. Air Canada has already cut its profit forecast, citing a decline in cross-border travel and economic uncertainty.