The first flight from MIA to MCO departs 6:54am and arrives at MCO at a “scheduled” time of 8:07am (Flight 2537).
Sdmccray1984, What date are you looking at? Based on OAG data for the remainder of this month, the first flight from Miami to Orlando is AA 1712 departing MIA at 0835 and arriving MCO at 0946. Today, the aircraft that operated that flight N908NN continued to Charlotte as Flight AA 1597.
The information you have for AA2537 MIA - MCO may be in error or the times and/or flight number may have recently changed.
is AA depending on that plane to arrive 20 minutes earlier than scheduled, giving it enough time for a 35-40 turn
I cannot speak for AA, but at my operator, the network and planning division would not schedule an aircraft turn that short--in the example you gave above, 8 minutes. They would not depend, or hope, for favorable conditions to exist every day so as to provide for an on-time operation.
Our business clients--both cargo shippers and major companies which have significant contracts with us for premium business travel--look at Department of Transportation "on-time" data, as well as other parameters, very closely before they award contracts to airlines, so it is in our best interest to schedule block times and turn times as realistically as possible. These companies continually monitor the data and will occasionally choose not to renew a contract and award business to another air carrier if the original airline is not meeting their requirements.
and yes, you could assign a different aircraft to operate the return trip with the same flight number, although I have rarely seen it done this way. Occasionally, yes, but not routinely.