JetBlue Airways has offered to buy Spirit Airlines for $3.6 billion, throwing a wrench into Spirit’s plan to merge with Frontier Airlines and create a behemoth budget carrier, the New York Times reported. Spirit and Frontier, both low-cost airlines, agreed in February to merge in a deal that the companies said would save consumers about $1 billion a year. JetBlue offered $33 a share in cash, Spirit said on Tuesday. Frontier’s shares have fallen since it and Spirit announced their deal, reducing the value of its offer, which has an implied value of about $25 a share at current prices. JetBlue’s chief executive, Robin Hayes, said in an interview that the acquisition would allow the carrier to offer more quality, affordable flights, helping it to better compete against the airlines that dominate the U.S. market. “This is about really allowing a bigger JetBlue to compete against four large legacy airlines, bringing the JetBlue experience to more customers, bringing more JetBlue flights into high-fare legacy hub airports and offering real competition,” he said. Spirit said its board planned to review the bid, which it described as “unsolicited,” and would “respond in due course.” After news of JetBlue’s offer broke on Tuesday, Frontier said in a statement that the acquisition would limit options and harm consumers.