Deutsche Lufthansa has agreed to acquire a 19 percent stake in JetBlue for $300 million. Lufthansa will also get a seat on JetBlue's board.

The deal is "the first significant investment by a European air carrier in a U.S. point-to-point air carrier," the companies said in a statement.

More such deals may follow, as foreign airlines exploit the weakness in the dollar while looking ahead to next year, when an open skies treaty between the United States and the European Union loosens the rules on trans-Atlantic flights.

"It's an opportunity for international carriers to take advantage of the weak dollar and buy distressed U.S. carriers," Marc Weinberger, head trader at W. Quillen Securities in New York, told Bloomberg News.

Any such deals would be minority stakes, as the United States still limits foreign ownership of American airlines to 49 percent.

Lufthansa's chief executive, Wolfgang Mayrhuber, said, "This investment presents Lufthansa with a compelling opportunity to invest in the U.S. point-to-point carrier market as the industry continues to evolve."

No code-sharing or other operational alliances are planned between JetBlue and Lufthansa for the moment. It is "simply a financial transaction," JetBlue's chief executive, Dave Barger, said on a conference call.

"At this point in time it's strictly a minority investment and we'll see where the future takes us with exploring other opportunities," he said, according to Reuters.

The investment is sorely needed by JetBlue, which has suffered from management turmoil and ugly fallout from a crippling ice storm last February. It also has a $433 million debt load.

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