DME will pick up early...your pickup time will be about 3:00 AM, give or take. Some people on this board who have early flights like that choose to stay the last night at one of the airport hotels, so they don't have to get up so early. I've left that early from WDW before...DME works same as usual, but the guests just look more sleepy. However, since the Resort Airline Checkin won't yet be open, you will need to take your luggage to the airport with you (under the bus), and check it in yourself.