Dulles is a suburb name, like the names used for many European airports (MXP, FCO, etc).ery few - the most obvious one - John Fitzgerald Kennedy, JFK; nearby I found Mayor Fiorello La Guardia, LGA.; maybe Washington Dulles - IAD
But there are plenty of others named after people in the US - MCO (Mccoy - for Orlando), MSY (Moisant) for New Orleans. But both of those are very old before any current conventions.