If Reid landed in Orlando at 8:05 P.M., we can work backwards to determine the time his first flight from Boston departed.
Reid's flight from Atlanta to Orlando was 1 hour and 20 minutes long, so it must have landed at 6:45 P.M. (8:05 P.M. minus 1 hour and 20 minutes).
Reid was in Atlanta for 2 hours and 35 minutes, so he must have arrived in Atlanta at 4:10 P.M. (6:45 P.M. plus 2 hours and 35 minutes).
Reid's flight from Boston to Atlanta was 2 hours and 50 minutes long, so it must have departed Boston at 1:20 P.M. (4:10 P.M. minus 2 hours and 50 minutes).
Therefore, Reid's first flight from Boston departed at 1:20 P.M.