In a 113-page decision released Jan. 16, U.S. District Court Judge William Young ruled in favor of the Justice Department in an antitrust suit filed last year to thwart JetBlue‘s planned $3.8 billion acquisition of Spirit Airlines.

The proposed merger, which was announced in July 2022, would create the nation’s fifth largest airline with more than 450 aircraft and a combined 77 million customers.

Last March, the Department of Justice filed a civil antitrust suit, invoking the Clayton Act, arguing that the merger would eliminate competition and further consolidate the nation’s airline industry – resulting in increased fares and reduced choices for travelers. New Jersey joined the lawsuit along with three other states. At the time, Attorney General Matthew Platkin noted a merger could mean JetBlue would control more than 12% of all passengers flying in and out of Newark Liberty International Airport, while the joint entity would control about 20% of routes at airports operated by the Port Authority of New York and New Jersey.

“There are no ‘bad guys’ in this case,” Young wrote at the top, summarizing a review of the evidence, testimony and exhibits presented during the four-week trial, which took place last year in Boston. “The two corporations are – as they are expected to – seeking to maximize shareholder value. The Department of Justice is – as the law requires – speaking for consumers who otherwise would have no voice.”

While Young conceded that a post-merger, combined firm of JetBlue and Spirit would likely place stronger competitive pressure on larger airlines, he stressed that it would likely harm “the consumers that rely on Spirit’s unique, low-price model,” which he believes would be difficult for another airline or combination of airlines to replicate.

“The Clayton Act was designed to prevent anticompetitive harms for consumers by preventing mergers or acquisitions the effect of which ‘may be substantially to lessen competition, or tend to create a monopoly,’” Young continued. “Summing it up, if JetBlue were permitted to gobble up Spirit – at least as proposed – it would eliminate one of the airline industry’s few primary competitors that provides unique innovation and price discipline. It would further consolidate an oligopoly by immediately doubling JetBlue’s stakeholder size in the industry. Worse yet, the merger would likely incentivize JetBlue further to abandon its roots as a maverick, low-cost carrier. While it is understandable that JetBlue seeks inorganic growth through acquisition of aircraft that would eliminate one of its primary competitors, the proposed acquisition, in this court’s attempt to predict the future in murky times, does violence to the core principle of antitrust law: to protect the United States’ markets – and its market participants – from anticompetitive harm.”

The judge did note the ruling narrowly applies only to the proposed merger as it was agreed to on July 28, 2022, and would not include that the defendants be permanently enjoined and restrained from carrying out this acquisition or a future one, as the government had initially requested.

“Such a broad injunction would prevent not only the proposed merger of JetBlue and Spirit as it currently stands, but also any future merger of the two companies,” Young wrote. “To rule in such a way would be prospectively to interfere with the free market with unknown, and perhaps harmful, competitive effects. Indeed, the defendant airlines and others in the market, in the context of the unique and dynamic market forces of the airline industry may decide to take another run at a merger at any time. The government will no doubt make its determination – as it is duty-bound to do – as to whether such a proposed merger sufficiently protects competition.”

In his closing, Young wrote that the court has made its best attempt to predict the future of a dynamic market recovering from the pandemic in uncertain times.

“Therefore, the court rules that the proposed acquisition violates Section 7 of the Clayton Act. Spirit is a small airline. But there are those who love it,” said Young. “To those dedicated customers of Spirit, this one’s for you. Why? Because the Clayton Act, a 109-year-old statute requires this result – a statute that continues to deliver for the American people.”

In a joint statement, JetBlue and Spirit said they disagreed with the ruling.

“We continue to believe that our combination is the best opportunity to increase much needed competition and choice by bringing low fares and great service to more customers in more markets while enhancing our ability to compete with the dominant U.S. carriers,” the companies said. “JetBlue’s termination of the Northeast Alliance and commitment to significant divestitures have removed any reasonable anti-competitive concerns that the Department of Justice raised. We are reviewing the court’s decision and are evaluating our next steps as part of the legal process.”

JetBlue operates out of Newark Liberty International Airport in Terminals A and B while Spirit operates in Terminal B.

The Justice Department did not immediately respond to a request for comment.