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 says a merger would be a better path out of bankruptcy for Spirit, as budget carriers struggle with high costs and competition.