CHICAGO (Reuters) -- Deutsche Lufthansa AG (LHAG.DE), Germany's national flag-carrier, will buy a 19 percent stake in low-cost U.S. airline JetBlue Airways Corp (JBLU.O) in a deal worth about $300 million, the two airlines said on Thursday.

The purchase marks the first major investment by a European carrier in a U.S. point-to-point airline.
The deal which requires approval from U.S. regulators, has the potential to bolster transatlantic operations for Lufthansa and its global partners. But no specific areas of cooperation between JetBlue and Lufthansa were announced.
U.S. law currently caps foreign ownership of U.S. airlines at 25 percent.
JetBlue Chief Executive Dave Barger said the deal is ""simply a financial transaction"" for now.
""At this point in time it's strictly a minority investment and we'll see where the future takes u.s. with exploring other opportunities,"" Barger said on an investor conference call.
Lufthansa said it will buy about 42 million newly issued shares of JetBlue, or 19 percent of JetBlue's equity after the issuance. The airline will pay $7.27 per share, or a total of about $300 million.
Barger said the Lufthansa investment would not change JetBlue's plans to remain a stand-alone carrier. ""From our point of view, our goal is still one of organic growth,"" he said.
Shares of JetBlue rallied as much as 25 percent earlier in the day on an unconfirmed press report of the deal. The stock pared gains and closed up 14.4 percent to $7.15 on Nasdaq after the confirmation. The deal represents a 16 percent premium to Wednesday's closing price of $6.25 and allows a Lufthansa nominee to be appointed to the JetBlue's board of directors when the transaction closes. One analyst said JetBlue's domestic route -- especially its strength in New York -- eventually could provide the foundation operational partnerships.
""This would be a strategic deal that would fill a gap in the Star Alliance,"" which is weak in the New York market, said Craig Jenks, president of Airline/Aircraft Projects Inc, a New York-based consulting firm.
The Star Alliance is a global airline partnership, of which Lufthansa is a founding member along with UAL Corp's (UAUA.O) United Airlines and U.S. Airways (LCC.N).
JetBlue ""provides a ready made feeder system for, not ju.s.t Lufthansa, but for all Star Alliance partners,"" Jenks said.
Britain's Virgin Group (VA.UL) owns a stake in new U.S. domestic carrier Virgin America.
The global airline indu.s.try has been recovering from a years-long downturn, and some experts believe carriers should consolidate to remove excess capacity and cut costs.
Talk of consolidation has been rampant in the U.S. airline indu.s.try for more than a year, although there have been no deals since 2005 when America West and U.S. Airways merged to form a new U.S. Airways Group.
Delta Air Lines (DAL.N) recently said it has hired advisers to help it consider strategic alternatives that could include a merger. The carrier denied it is in merger talks with United Airlines. UAL leaders have long advocated mergers of domestic airlines and the lifting of restrictions on foreign ownership.