Currently, February is the cheapest month in which you can book a flight from Greenville, North Carolina to Washington, D.C. Reagan-National Airport (average of $278). Flying from Greenville, North Carolina to Washington, D.C. Reagan-National Airport in March is currently the most expensive (average of $335). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.