United Airlines will add three new domestic routes at its Denver hub.

Daily flights to Greenville/Spartanburg, South Carolina, and Syracuse, New York, will begin June 6 and will operate year-round. Flights to Portland, Maine, start June 8, but they’ll operate only on weekends during the summer schedule. (Scroll down for full schedule details)

All three of the new routes will go head-to-head against service offered by Denver-based budget rival Frontier Airlines.

The routes add to other previously announced United routes to Charleston, South Carolina; Eureka, California; and Fairbanks, Alaska. Those flights also begin June 6.

In other details announced Thursday, United will expand its existing weekend-only summer service to Burlington, Vermont; Savannah, Georgia; and Pensacola in Florida. A Sunday round-trip flight is being added to those routes, which currently fly only on Saturdays.

Also getting more flights will be United’s service between Denver and Fort Myers, Florida. The route previously operated only during the winter, but will now be offered Saturdays and Sundays during the summer and fall until daily service resumes as scheduled in October.

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The latest routes were announced the same day that United put its new “rebanked” schedule into effect at Denver. The airline has tweaked schedules on its “banks” of incoming and outgoing flights, trying to better match connecting passengers with flights.

United says the schedule adjustment – which began Thursday (Feb. 14) – will boost the number of morning flights available to business customers traveling from Denver to the East and West coasts while also improving connecting options for customers traveling to or from the airline’s Midwest and Mountain Region destinations. The effort was first announced last fall.

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