Spirit Airlines, now in Chapter 11, is a vital part of keeping fares low at Chicago O’Hare and other airports.

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.

In attempts to prevent a bankruptcy filing, Spirit announced in October that staff layoffs would take place as part of $80 million in cost-saving measures. It also said it had reached an agreement to sell 23 jets to GA Telesis, an aviation services company, for $519 million.

Spirit Airlines said Monday that it's filed for bankruptcy protection and will attempt to reboot as it struggles to recover from the pandemic -caused swoon in travel and failed attempts to sell itself to other carriers.

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.

The company has reassured passengers that its Chapter 11 bankruptcy will not affect their bookings and that staff will still be paid.