The airline boosted guidance for the current quarter. Frontier Group Holdings (ULCC 5.71%) is feeling more upbeat about the current quarter, and investors are happy to go along for the ride. Shares of the discount airline opened up as much as 12% and were trading up 8% at 10 a.m. ET after Frontier raised its margin guidance for the quarter. Not as bad as feared Investors aren't sure what to think about airline stocks right now. The industry has done well since the end of the pandemic, but a combination of h ...