This first part of the question regards the flight at the end of The Dark Knight Rises:
At the end of The Dark Night Rises, Batman appears to be flying away in his "bat" with the A-Bomb attached to it. The bomb has a blast radius of 6 miles, yet he managed to fly it so far away from the shore it looked like a little cloud of smoke. However, when he was carrying the bomb he was having trouble getting "The Bat" up and out of the city. How could he have possibly gotten it that far away from the shore in such as short amount of time?
This second part of the question regards the fate of certain characters in the film.
The other question that I am sure will be asked all over for the next few weeks: what actually happened to the Batman? As we learned, the autopilot was installed - did Batman jump out of the "bat" before it blew? Or did he really make the ultimate sacrifice?