The Justice Department (DOJ) sued Tuesday to block JetBlue Airways Corp. (JBLU) from completing a $3.8-billion takeover of Spirit Airlines Inc. (SAVE).

The DOJ expressed concerns for budget travelers, the main customer base of low-cost carrier Spirit. The government argues that these travelers will have fewer options if the merger is allowed to move forward.

The two companies have reportedly been expecting legal action for the past few weeks. For his part, JetBlue's CEO Robin Hayes said antitrust regulators "came to the table with their minds made up" on stopping the merger.

Airlines Say Merger Will Boost Resilie𓆉ncy, Cut Co꧑sts

JetBlue and Spirit agreed in mid-2022 to combine to form the world's fifth-largest airline. The combination would have a market share of about 9%, placing it behind larger rivals such as American Airlines Group Inc. (AAL) and Delta Air Lines Inc. (DAL).

Spirit is a bargain airline that charges fees for add-ons, while JetBlue offers a higher-end customer experience. JetBlue plans to reconfigure seating plans and repaint Spirit aircraft.

Still, there are reasons to believe the deal may go through. Florida Attorney General Ashley Moody said this week that her office's concern had been resolved by a settlement agreement with the two companies that she expects to bring new jobs to the state.

Executives at both JetBlue and Spirit say that the merger would best position them to compete against larger rivals. They've also told antitrust regulators that the merger will benefit customers through cost savings, additional service to smaller cities, and boosted resiliency during weather and other flight disruption events.

JetBlue and American also face a separate DOJ suit about the two companies' plans to sell tickets on each other's flights. The Department alleges that the deal makes the two airlines collaborators, reducing competitive pressure.

If the deal is blocked by the DOJ, JetBlue has agreed to pay Spirit $400 million in breakup fees.