Frontier and Spirit Airlines will once again try to merge, only months after the Biden administration won a key antitrust court battle to block an attempt by JetBlue to buy Spirit. A combination of the two ultra-low-cost carriers would produce the country’s fifth largest airline,

Spirit, which filed for bankruptcy protection last year, says it has rejected the new Frontier overture but would be open to a higher offer.

Frontier tried to merge with Spirit in 2022 but was outbid by JetBlue. However, the Justice Department sued to block the $3.8 billion JetBlue deal, saying it would drive up prices for Spirit customers who depend on low fares, and a federal judge agreed in January. JetBlue and Spirit dropped their merger bid two months later.