JetBlue Airways has offered to buy Spirit Airlines for about $3.6 billion and break up a plan for Spirit to merge with rival budget carrier Frontier Airlines. Spirit said it would evaluate the JetBlue bid and decide what’s best for its shareholders.

“The combined company would maintain the JetBlue brand and continue to be based in New York City,” JetBlue said in its statement. “The current merger proposal assumes the rebranding and retrofitting of Spirit’s fleet as JetBlue, introducing a superior onboard experience to Spirit customers.”

“If the JetBlue offer is accepted by Spirit and if the Department of Justice approves this merger, it would enable JetBlue to expand dramatically by reallocating Spirit’s aircraft on different routes, potentially even giving JetBlue enough aircraft to open another hub somewhere perhaps in the center of the country.”