On Friday the 29th

FLT 3185 (1055am dept) has 70 of 86 seats open (Express so no FC)
FLT 2211 (0150pm dept) has 56 of 70 seats open (Express so no FC)

The CLT-CDG flight (#770)has 13 of 17 Envoy and 28 of 186 coach seats open.

FWIW, flt 754 PHL-CDG has 15 of 29 Envoy and 66 of 263 coach seats open. There are plenty of open seats DCA-PHL to connect with the PHL-CDG flight, but no US IAD-PHL flights but UA should have something.

Jim