Two of the country’s biggest budget airlines are merging together to create one mega low-fare flying company. Frontier Airlines and Spirit Airlines announced the deal Monday morning, which is valued at $6.6 billion.

The combination is being billed by the company CEOs as a merger of equals, but Frontier has a slight edge with a 51.5% shareholder stake, while Spirit will take 48.5%. The goal, according to merging documents, is to create the country’s most competitive ultra-low fare airline.

Together, Spirit and Frontier would be the fifth-largest airline in the country, behind American Airlines, Southwest Airlines, Delta Air Lines and United Airlines.

“Our team members win with 10,000 more direct jobs in the next couple of years as well as thousands more with our business partners, so everyone’s going to win,” Frontier Airlines CEO Barry Biffle said on CNBC.

The companies still have to work out a lot of details, from the name of the combined airline to who will serve as chief executive to where the company will be headquartered. Frontier is based in Denver while Spirit is headquartered in Miramar, Florida. Biffle said all will be announced “in due course.”

But the companies will also have to get the deal through the Biden administration, which has said it’ll be tough on mega mergers. The airlines argue merging together will allow them to more aggressively compete with the Big Four airlines, but it’ll be up to federal regulators to determine that merging the two biggest ultra-low cost carriers won’t decrease competition in the skies.