Ben Mutzabaugh

USA TODAY

United is further growing its footprint in San Francisco, announcing three new routes from its main West Coast hub.

Airbus A319 service to Cincinnati and Detroit will begin June 8, with one daily round-trip flight on each route. United will go head-to-head on both routes against Delta, which operates a hub in each of the Midwestern cities.

United also will add seasonal service from San Francisco to the Kalispell, Mont. The Saturday-only flight – geared toward Bay Area skiers – will launch Dec. 17 and run through April 1 on Bombardier CRJ 700 regional jets. United also flies to Kalispell from its Denver hub -- offering at least twice-daily service during the winter season -- and from Chicago O'Hare, offering weekend-only service.

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The San Francisco announcement comes just a month after United revealed plans to add two Florida routes to its route map there. United also has recently announced plans to expand its schedule at another Bay Area airport, adding routes from San Jose to Newark Liberty and Chicago O’Hare.

As for the latest San Francisco service, United's new flights will put it into head-to-head competition with Delta. Detroit Metropolitan Airport says the San Francisco route was its busiest without competition. The service brings United back to the route after an absence of more than 25 years, according to the Wayne County Airport Authority that runs the Detroit airport.

“Ensuring our community has excellent access to air service in our top markets has been a priority for our team,” aviation authority CEO Thomas Naughton says in a statement. “The addition of United’s new service to San Francisco is a tribute to the rising strength of our economy, and our team’s hard work and diligence in addressing the growing demand for air service here in our region.”

In Cincinnati (CVG), United will go up against Delta and discount carrier Frontier on the nonstop route to San Francisco.

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“United has seen significant growth at CVG over the last three years,” Cincinnati airport chief Candace McGraw says in a statement. “Since 2013, United’s passenger boardings have grown more than 44% as a result of expanded schedules and placement of larger aircraft.”

“This new service will offer tremendous convenience and value for travelers, including a great schedule to San Francisco as well as one-stop connections to 30 other destinations including Singapore, Sydney, Australia, Auckland, New Zealand and many popular Asia destinations,” McGraw adds.

Delta has dramatically scaled back its operation in Cincinnati during the past decade, but still considers the airport to be one of its hubs.

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