FWIW, I think the clues will be random, and will have one of two flights in each envelope. But teams won't know if its the earlier arriving flight until they check in at LAX. (Which would be different, and build in the penalty of the later arriving flight and teams will be rushing to the airport because if they had the first flight, they don't want to be late.) They haven't done it that way ever IIRC for the first flight, and it would shake the teams up early.