The Massachusetts Bay Transportation Authority board Thursday unanimously approved long-awaited plans to extend commuter rail service from Boston to T.F. Green Airport in Warwick, and ultimately to Wickford Junction in North Kingstown.

MBTA officials said the train service from Boston to Rhode Island, tentatively scheduled for eight trips a day, is not scheduled to begin until 2011. The new station at T.F. Green is scheduled to open in September 2010. But officials in both Massachusetts and Rhode Island said that if the Warwick station and the rail infrastructure are ready, there could be trains running from Boston to Warwick by the fall of 2010.

The Warwick station is part of a $267-million project that includes a parking garage and rental car facilities. It’s connected to the airport terminal by a 1,200-foot skyway that spans Post Road.

Kevin Dillon, president and chief executive officer of the Rhode Island Airport Corporation, said the facility is on schedule for a September completion. He said his understanding is that full MBTA service won’t begin until the spring of 2011, but he anticipates there will be preliminary train service from Boston when the T.F. Green station opens.

Charles St. Martin, spokesman for the Rhode Island Department of Transportation, said the MBTA’s plans involve train service all the way to the Wickford station, which is not due to be completed until sometime in 2011. But St. Martin said the goal of the Rhode Island DOT is to have limited MBTA service as far as T.F. Green before then.

Joe Pesaturo, spokesman for the MBTA, said that if the state DOT gives the MBTA the go-ahead for service to Warwick, the MBTA will “make every effort to accommodate them.”

Warwick Mayor Scott Avedisian said Thursday’s MBTA board decision makes it easier to deal with critics who insisted the T.F. Green intermodal project would never get train service.

Dillon said that whenever MBTA train service does start to Warwick, he considers eight trains a day as just a starting point. “That’s the baseline. I fully expect the number of runs will increase, and ultimately we will try to tie the trains into our flight schedules.”

Dillon said the MBTA board vote was expected all along, but it’s nice to have it formalized. “It’s another significant milestone in the ongoing completion of the project,” he said. Dillon said rail service will make T.F. Green more convenient to the Boston market, and more attractive to international travelers who are accustomed to easy connections between airports and trains.

asmith@projo.com