I would like to understand the process for transferring through DFW from YYC on AA, to LHR on BA. Below, I have copied from the wiki but am unclear if YYC and/or LHR are on the “approved” list. Also, would we be pre-cleared at YYC? I notice that AA flights from YYC generally arrive at terminal C, so I am guessing they are regarded as ‘domestic’ and pre-clearance takes place in YYC.
At the heart of my question is a potential itinerary that sees me arriving in DFW at 17:50, for an outbound BA flight at 18:55.
Finally, I do understand there are direct alternatives for YYC-LHR but this would be a OneWorld booking.
From the wiki:
There is no international transit process in most U.S.A. airports, but (DFW and MIA have a ITI baggage exception for international to international if arriving from some "approved" international origins). Arriving internationally, unless you have been pre-cleared or are excused by meeting ITI requirements as described here, you must proceed through U. S. immigration (there are kiosks and a fast channel for Global Entry approved passengers, and a "green line" for those with no checked bags), recover your baggage from the baggage carousel and proceed through U. S. Customs. There is a "green line" shortcut for passengers traveling only with carry-on baggage (no checked luggage) and there are Global Entry kiosks and a short cut to Global Entry queues.
Upon exiting Customs there is a bag drop facility; drop your checked connecting baggage, exit to the landside arrivals area.