Spirit Airlines has been given a two-month extension to refinance about $1 billion of its debt, which was due on Monday. The largest Florida-based airline has been renegotiating $1 billion of its bonds as its stock price plummets.

Spirit Airlines’ stock swelled by 60% on Monday, on track for the low-cost airline’s best day since going public, after the carrier announced an extension to refinance its debt while temporarily avoiding the threat of bankruptcy.

Spirit Airlines extends its debt deadlines amid bankruptcy speculations, while JetBlue's founder argues that Frontier would have been a better match after their failed merger.