Spirit Airlines has completed the Chapter 11 bankruptcy process, and is "emerging as a stronger and more focused airline," chief executive Ted Christie said Wednesday.

Ultra-low-cost carrier Spirit Airlines has completed the Chapter 11 bankruptcy process, with chief executive Ted Christie pledging to focus on continued upgrades to the airline's products.

In an evolution from its budget-exclusive roots, Spirit is attempting to tap into the growing market for more upscale travel. It is now offering flight options with tiered prices,