Spirit Airlines filed for bankruptcy just before the busiest Thanksgiving for air travel in history. But the loss of Spirit undoubtedly would lead to fare hikes nationwide.

The disparity in size between the low-priced airlines and the top firms underscores a fissure in the industry separating budget carriers in select markets from the major airlines that dominate flight offerings nationwide, Mike Boyd, president of aviation consulting firm Boyd Group International, told ABC News.

Unease around the bankruptcy petition may have some travelers looking elsewhere for flights ahead of the busy holiday travel season. Here's what you need to know.