The best price found from United States to Lithuania is on May 29th, 2017, travelling with Aeroflot. See more options, compare prices and book: search flights.
AirBaltic (www.airbaltic.com) Flies to Vilnius from Rīga several times daily and from Tallinn on most days. Also offers scheduled if sporadic service from Rīga to Palanga. These flights are more common in summer (May to September).
Estonian Air (www.estonian-air.com) Flies between Tallinn and Vilnius twice each weekday.