There are three airports within 70 miles of Fredericksburg, VA:
Richmond International Airport (RIC)
Reagan National Airport (DCA)
Dulles International Airport (IAD)
Although all three are about the same distance in miles, they are very different in travel times from the airports to Fredericksburg. Vehicle traffic in the Metro DC area is very heavy, particularly during rush hour, and travel times can vary dramatically.
On a “good” day (depending on the time of day) travel to and from DCA or IAD can vary from 1.5 hours to 3 hours.
Typical travel from Richmond airport to Fredericksburg is 1 hour 15 minutes. The only time this will vary is if there is an accident on the northbound lanes of Interstate 95, but there are other routes to take off of interstate 95.
If it were me – I would fly in and out of Richmond – just saying.