After months of bankruptcy rumors growing increasingly louder, Spirit Airlines (SAVE) has been on a relative roll lately. The airline’s shares soared by as much as 73% after it managed to restructure its debt load in a way that would extend its payment deadlines until the end of December and give it the $1 billion in liquidity that will allow it to stay operational until at least the end of the year.

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.

Kevin Carter / Getty Images Spirit Airlines shares surged higher Monday morning as the carrier said it extended a deadline for debt refinancing with Visa and Mastercard. The discount airline also said it has used all of a $300 million revolving credit line ...