JetBlue Airways Corp. is flying a new course after its move to acquire Spirit Airlines, Inc. was nuked by a federal judge last month.

News hit late Monday that activist investor Carl Icahn has acquired 9.91% of the low-cost carrier, sending shares up more than 14% in premarket trading in New York.

As explained in a filing, Icahn believes JetBlue is “undervalued and represented an attractive investment opportunity.”

The filing continued: “The Reporting Persons have had, and intend to continue to have, discussions with members of the Issuer’s management and board of directors regarding the possibility of board representation.”

In recent years, JetBlue has lost money and experienced operational challenges. The new CEO, Joanna Geraghty, who assumed her position on Monday, has committed “aggressive action” to guide the airline out of financial turbulence and into blue skies of profitability.