The Green Mountain Flyer was an international day train between Montreal, Quebec, Canada, and the Northeast United States, with sections to New York City and Boston.

The trains' route, running south, began in Canadian National Railway territory from Montreal Central Station to the Canada–United States border at Rouses Point, New York.

[10][11] Since 1974, Montreal–New York train service has been provided by Amtrak's Adirondack, the successor to a one-time Green Mountain Flyer competitor: the Laurentian.

In 2022 the Vermont Agency of Transportation (VTrans) and Amtrak extended the Ethan Allen Express from Rutland to Burlington over the line formerly used by the Green Mountain Flyer, restoring Burlington–New York service.

[12] VTrans has also proposed adding a second Burlington–New York train via North Bennington and Manchester that would more-closely match the former route of the Green Mountain Flyer.