Investing.com -- Shares of JetBlue Airways Corporation and Frontier Group Holdings Inc are trading higher in pre-market on Monday following the shutdown of Spirit Airlines over the weekend.

JetBlue is up over 4.1% while Frontier Group is also up roughly 4%, both extending gains from Friday.

Spirit, once a major U.S. low-cost carrier, announced its shutdown early Saturday after years of losses.

"To our Guests: all flights have been cancelled, and customer service is no longer available," the company said in a statement on its website. "We are proud of the impact of our ultra-low-cost model on the industry over the last 34 years and had hoped to serve our Guests for many years to come."

The shutdown leaves more than 15,000 of its employees without jobs.

JetBlue and Frontier Airlines as well as other U.S. airlines announced plans to assist affected passengers with travel plans.