Low-cost carrier Spirit Airlines has announced four new routes, boosting its presence at Houston and Denver.
From 4 October, the carrier will launch daily non-stop service between Houston George Bush Intercontinental Airport and Chicago O'Hare and daily non-stop service between Houston and Las Vegas.
Spirit first announced in July that it was adding Houston to its network with non-stop twice daily flights between Houston and Dallas-Fort Worth, to begin on 20 September.
United Airlines operates multiple flights daily between Houston and Chicago, both of which are hubs in United's network. American Eagle also offers non-stop service on the route, schedules in Innovata show. On Houston-Las Vegas, Spirit's entry will break United's monopoly on the route. The mainline carrier operates several non-stop daily flights between the two cities.
Spirit will also launch daily non-stop service between Denver and Phoenix-Mesa Gateway Airport from 4 October, adding its fifth destination from Denver.
Spirit first began flights to Denver in May, with connections to Dallas, Chicago, Las Vegas and Fort Lauderdale. Spirit has been focusing of late on growing its network out of other cities instead of its Fort Lauderdale base.
Low-cost rival Frontier Airlines recently announced it will launch service between its Denver base and Phoenix-Mesa from 15 November, and will be the only competitor on the route for Spirit. Several carriers, including US Airways, Southwest Airlines and Frontier, already operate non-stop between Denver and Phoenix Sky Harbour International Airport.
Separately, Spirit will launch daily non-stop service between Portland and San Diego from 8 November. Alaska Airlines is currently the only airline operating non-stop on that route.