I am going to fly to ATL (Georgia) and then to IAD (VA) and go home in MD. Is a PCR test required to be able to fly to the USA?
No. So far, the only country from which travel to the US requires a negative COVID test is the UK, in an order that took effect December 28, 2020. As of this writing, the CDC has not made such an order about any other country.
Update: Starting January 26, 2021, a negative COVID test within 3 days of boarding the plane will be required for travelers by air to the US from all countries.
According to Reuters, the US may expand Covid-19 testing for more countries.
Check this page, enter from the Netherlands and search below for the United States. As you can see in the Link (point 6) only passengers arriving from the UK will need a test, for the moment....