Originally Posted by
GeraldHouse
Can a Canadian come in from the US and depart on the same plane back to the US without going through customs? If not, would it still be possible to board the same plane going back (within 20 minutes or so)? No checked baggage.
The quickest US inbound to US outbound is iff your flight arrives to T1. You will be at Int'l arrivals. There is a CBSA checkpoint for Int'l arrival tapransiting to US. Once pass this checkpoint you will be at the CBP US departure preclear area where you use the kiosk for passport or GE. There might be a CATSA security checkpoint as well.
20 minutes? Possible but not probable.