It can vary depending on the specific flight and airline you are looking at. Generally speaking, prices for flights into Dulles International Airport (IAD) and Reagan National Airport (DCA) are similar, as they are both major airports serving the Washington, D.C. metropolitan area. However, it is always best to check the specific prices for your desired dates and routes to get an accurate comparison. Other factors to consider include the location of your destination, the time of your flight, and the amount of time you have before your connecting flight. In terms of airport parking, DCA parking will be a little bit more expensive than Dulles airport parking options.