I want to know the answer to the following question:
In additions, the train line is also connected with which airline services?
All the background I'm provided with is that "Union Station is further served by four Amtrak lines: the Northeast Regional and the high-speed Acela Express provide service to New York, Washington, D.C. and Boston, and rank as the first and second busiest routes in the country; the New Haven–Springfield Line provides service to Hartford and Springfield, Massachusetts; and the Vermonter provides service to both Washington, D.C., and Vermont, 15 miles (24 km) from the Canadian border.". Is that enough to answer the question?