Low-cost giants Frontier Airlines and Spirit Airlines announced a groundbreaking merge agreement in February, but JetBlue Airways just made a “superior proposal” for Spirit.

On Tuesday, JetBlue confirmed that it has placed a bid of about $3.6 billion to acquire Spirit, with “an adjusted enterprise value of $7.3 billion.” The news may ruffle feathers with budget rival Frontier, which planned to purchase Spirit for $2.9 billion. Read More from Business Insider.