Your IT is horrible for not posting counter hours. I'm surprised any airline would do that. But ya, I checked my AA hours and it's 4am for me on a wednesday last time, although the AA's TA didnt really start til around 4:15am. So my memory should be right, 4am for DL.

My reference to pre-clearence is US customs which you clear in YYZ.

nwdogahunt, if you don't mind rushing a bit, I probably advise getting there around 4:45am. One, there is no SC past security and barely anything worth buying past security. The Admiral's club there is one big reason I fly out of there. Two, the people lining up around 4-4:30am all get jammed up waiting for the custom people anyway and things start to clear up around that time, so you can get a few more mins of snooze. The only worry you have is usually on a friday long weekend and around christmas when if people are going away and don't know what they are doing. That AA 6:10am flight to MIA has the most snowbirds/wheelchair seniors I ever seen, aka worst kettles ever! I will check the loading of that flight in determining to show up early or not. Any question, post on the thread or PM. I'm not really a DL regular so it might take me a little longer to respond, sorry.