Spirit Airlines will add five daily routes from Boston this summer.
Service to Charlotte and Dallas-Fort Worth will begin on June 7. On July 5, Spirit will begin flying Boston-Los Angeles.
Then on Aug. 9, the budget carrier will begin flights from Boston to Houston Bush Intercontinental and Phoenix.
With the additions, Spirit will fly 12 year-round routes from Boston as well as two winter seasonal routes to Florida.
The moves will bolster Spirit at an airport where potential merger partner JetBlue has a large presence. JetBlue has a 30.5% market share in Boston, according to the DOT's Bureau of Transportation Statistics.
Antitrust regulators at the Justice Department have filed suit to block JetBlue's acquisition of Spirit.
On the Boston-Dallas route, Spirit will compete against JetBlue, American and Delta. Spirit will compete against those same airlines on Boston-Charlotte and Boston-Phoenix.
On the Los Angeles route, Spirit will compete against JetBlue, American, Delta and United.
United and JetBlue are the current carriers serving Houston Bush Intercontinental from Boston.