Spirit Airlines rebuffs acquisition offer from JetBlue

• Spirit will instead be going forward with their planned merger with fellow low-cost carrier Frontier, which was announced in February. The deal is set to create the fifth-largest U.S. airline.

What they're saying: "Spirit continues to believe in the strategic rationale of the proposed merger with Frontier and is confident that it represents the best opportunity to maximize long-term shareholder value," Mac Gardner, the chair of Spirit's board of directors, said in a statement.

• In a letter to JetBlue CEO Robin Hayes, Spirit executives wrote that the proposed deal between the two airlines "has a low probability of receiving antitrust clearance" due to JetBlue's partnership with American Airlines, known as the Northeast Alliance.

State of play: Last year, the Justice Department sued JetBlue and American Airlines over their planned partnership on the basis that it is anticompetitive. A number of states have also sued to block the partnership, per the New York Times.

• Spirit executives wrote in the letter that JetBlue's response to their concerns about the Northeast Alliance "makes clear that JetBlue is unwilling to terminate the NEA."

Editor's note: This article has been corrected to reflect that JetBlue offered to buy Spirit Airlines for $3.6 billion, not $3.6 million.