When I first saw Dragonflies I immediately thought it would be great to get them in flight, but quickly realised it was an almost impossible task (especially with the FZ300 I was using then). Then I found there were one or two species that do hover for a few seconds every now and then. So it became a matter of patience. As you say, when they are darting around, there is just not enough time. I tried using pre-capture to get them taking off. Even then, at around 10 frames / second, there is at best only one frame before it's gone - and he's mostly out of the focal plane. I need a camera with 50 f/s and re-focus every frame.
I knew that I would eventually get this one if I waited long enough - but had given up many times.
Thank you Doctor, apreciado