If you want a cheap flight from Birmingham to Washington DC, you've got two airlines to choose from.
Washington DC Ronald Reagan Washington National Airport is just one of the airports in Washington DC. If you're not set on a specific airport, try changing your search from Washington DC Ronald Reagan Washington National Airport to Washington DC to see a broader range of flights – they might be cheaper. It usually takes about 14 hrs 50 mins to fly 5769 km to Washington DC Ronald Reagan Washington National Airport.
50 flights go to or via Washington DC every week. The most popular airline is United Airlines but do spend some time checking all your options – they aren’t necessarily the cheapest airline to book with.
If you're planning on going to Washington DC during this time, you could take a look at other airport options. Or you could try to get a last-minute bargain.