When Spirit Airlines filed its Chapter 11 bankruptcy petition in New York last week, one of its top executives offered the court a note of optimism. The troubled South Florida-based airline, said Fred Cromer, an executive vice president and chief financial officer in a court declaration, was entering its financial overhaul process “with an eye towards continuing to deliver low-cost, high-quality service to its loyal customers, and to do so for years to come.” The question is, does the pioneering discounter have enough time to transform its service profile from a maverick bare-bones carrier to a more upscale airline? On approach to one of the busiest Thanksgiving travel seasons in memory, Spirit flew as usual last week after filing a “prearranged” Chapter 11 bankruptcy petition designed to quickly reduce a large chunk of debt in a restructuring deal with lenders that calls for the creditors to take $350 million in newly created equity in the airline.