Originally Posted by
Alpha Golf
There are no sterile international connections at Dulles, so you'd have to clear immigration/customs/security. To me not worth the hassle.
Originally Posted by
cheltzel
The OP is flying from YYZ, a CBP preclearance airport. Luggage should be checked through and no security clearance will be required. Flights form YYZ will arrive as if they arrive from a US domestic airport.
I'd assume too the OP would be coming back, so would still have to clear once in IAD and then again in YYZ and only their passport can determine how simple or less so that's likely to be. Canadian passport would be through in a few minutes, even better with NEXUS card, but if they are an Egyptian living in Canada then I'd probably avoid IAD it in that direction.
All that said, I think March is too early for widespread acceptance of flights from the US, while flights from Canada will likely be allowed fairly soon. At this point I'd worry about that a lot more than 777 vs 787.