Frontier Airlines said Wednesday it has again proposed merging with struggling rival Spirit Airlines, which is in bankruptcy.

Frontier and Spirit first announced a deal to merge in 2022, but a JetBlue Airways offer derailed that plan. JetBlue’s proposed acquisition of Spirit was blocked by a federal judge last year, and Spirit filed for bankruptcy protection in November.

Frontier said in a release that it has met with Spirit’s board and executives since it made its proposal this month. Frontier executives said in a email to counterparts at Spirit this week that their plan is better than Spirit’s own plan to emerge from bankruptcy.

“We continue to believe that under the current standalone plan, Spirit will emerge highly levered, losing money at the operating level, and this would not be a transaction we would pursue,” wrote Frontier Chairman Bill Franke and CEO Barry Biffle in a Tuesday email to Spirit Chairman Mac Gardner and CEO Ted Christie. “As a result, time is of the essence.”

Christie and Gardner told their Frontier counterparts that they were rejecting the deal, calling the terms “inadequate and unactionable,” according to a letter shared in a securities filing on Wednesday.

Spirit said it expects to exit Chapter 11 bankruptcy this quarter. It has cut costs recently, including by slashing some 200 jobs and selling some of its Airbus planes. The airline had also been particularly challenged by a Pratt & Whitney engine recall that grounded dozens of its jets.

Budget carriers like Frontier and Spirit have struggled post-pandemic, as costs like salaries have risen and consumers have opted for trips abroad on carriers with options for roomier and more expensive seats.

Both Frontier and Spirit have been working to upend their business models that were marked by low fares and fees for add-ons from seat assignments to cabin baggage.

The airlines last year did away with cancellation and change fees for some of their tickets and started bundling perks along with tickets. Frontier last year said it would start offering a premium section at the front of the plane.