ToplineSpirit 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.The budget airline fell to a new record earlier this month as it reportedly considered bankruptcy.GC Images Key FactsSpirit’s shares increased to over $2.30 as of around 1:15 p.m., pacing the stock’s best day since a 37% spike on March 24, 2020. On Friday, Spirit disclosed a ...