You should definitely leave a couple of hours at least between the first flight landing and the second flight taking off. Reagan is a small airport, but there are separate terminals for small airplanes versus larger ones, and the shuttle from New York to DC will arrive in the smaller terminal. You will have to move to the larger terminal to connect with your group, most likely.
It depends on time of year and how important it is to be on the Paris flight. When airports go into delays, the shuttle flights are at much higher risk for longer delays and/or cancellations. Thunderstorm season and late winter are the worst. When I need to connect to a cruise ship, I arrive the evening prior and stay overnight in a local hotel. If you really need to be on the CDG flight, I'd plan to fly in the evening prior. Enjoy your Paris trip!
Thank you all
All depends on what time the flight to paris leaves. Then its a matter of airline and arrival time to meet flight on time to paris.
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