One would think that less than a month before Thanksgiving, and two months before the Christmas-New Year’s holiday season, this is not an ideal time for news pages to be filled with reports about an airline’s possible bankruptcy filing, or renewed takeover talk by an old suitor, or a spate of layoffs looming in January. But the public discussion is one of the realities facing South Florida-based Spirit Airlines as the carrier’s management labors to raise cash and plot a course to return to profitability amid fierce industry competition. Travelers have choices when they book trips for the year’s busiest travel seasons.