This was a lucky shot, it was a very foggy morning which meant you could only hear the aircraft coming but not see it until it was right on top of you and I had my zoom on 200 when it should have been about 70. In fact I was surprised it took off at all, even the sea gulls were grounded that morning.
...don"t you feel like Hercules with a "Galaxy" over your shoulder?? Perhaps 70mm would have been better, but you did get the shot, it is in focus and you never fell and broke your camera! This is the reason that they make a roll of film with more than one shot on it.....you have another chance. Please keep trying, Rome was not built in one day!