Back in 2008, I spent several hours over the summer at a double-crested cormorant rookery to photograph and observe the birds. In my attempts to photograph them, I immediately learned three things about cormorants; they are terrible at taking off, they fly very, very fast, and their only means of obtaining food is through diving.
I have a very strict rule for photography and that is "know your subject" and use whatever means and resources you have to learn. Of course, time in the field is the best way to learn. When I sat for hours at the rookery photographing, I had lots of opportunities to practice flight shots and learn flight patterns so that I could anticipate some shots. However, I also believe it does not hurt to spend time reading. Through observations and following up these observations with internet and book research on bird physiology and behavior, my bird photography technique has improved. That's not the only reason for my research, I also love physiology and birds just fascinate me to no end.
And that's it! High flight speed and terrible take-offs and landings are characteristics of a successful diving bird. So if you want to practice flight shots, challenge yourself and look for the cormorant.