SS255
Veteran
No question about the congestion (although US is doing it's best to turn CLT into hillbilly Philly). For the record, however, European flights would go up the east coast departing CLT for Europe, passing not too far from EWR, JFK, PHL, and IAD to make a difference. Likewise on the return.
Jim
I was going to make a reference to this, but I thought it would make my post too wordy. I should have known that nothing would slip past you, Jim.

Connecting through EWR, JFK, PHL & IAD is just too much of a PITA if there is a better alternative in the SE.