United Airlines targets bankrupt Spirit’s main markets with additional flights

United Airlines on Thursday rushed to cash in on rival Spirit Airlines' financial troubles, beefing up its footprint in the bankrupt discount carrier's main markets, including Fort Lauderdale, Orlando and Las Vegas.

Spirit Airlines, which filed for its second bankruptcy protection last week, has been shrinking its operations and retreating from a number of markets, which has opened up an opportunity for rivals.

Last week, Frontier Group introduced flights to Spirit's strongholds.

"If Spirit suddenly goes out of business, it will be incredibly disruptive, so we're adding these flights to give their customers other options if they want or need them," said Patrick Quayle, United's senior vice president of Global Network Planning and Alliances.

United will start selling tickets on Thursday for new flights to 15 cities, where Spirit operates. The Chicago-based airline said it will fly larger aircraft between Chicago and New York LaGuardia to help customers outside of its hubs to connect to the newly added flights.

"We expect these carriers to continue to see a sizable benefit from Spirit's retrenchment, despite having less total overlap," TD Cowen analyst Tom Fitzgerald wrote in a note earlier this week.