The news of Spirit Airlines preparing for bankruptcy is critical for investors as it directly impacts the company's financial stability and future operations. The failed merger talks with Frontier Airlines suggest a lack of viable alternatives to avoid bankruptcy, likely leading to a negative short-term impact on Spirit's stock price.

The failure of merger talks with Spirit Airlines may affect Frontier Airlines' strategic growth plans. However, the direct impact on Frontier's stock price is less certain compared to Spirit, as the news primarily concerns Spirit's bankruptcy preparation.