DPReview is at CP+ 2015 in Yokohama Japan. We found a large diorama at the Sony booth with a model bird circling above a fabricated landscape. Here's a Sony A6000 focusing on & tracking that bird in flight using what Sony is calling '4D Focus' - which is essentially three-dimensional continuous focusing (a la Nikon '3D tracking').
Also known as 'Lock-on AF' in Sony's menu system, '4D Focus' is rather impressive (in good light, anyway), functioning here even at 11fps. The image sensor handles subject tracking extremely well, while the on-sensor phase detection elements ensure quick focusing on the tracked subject.
Recently, we're seeing incredible advances in AF through the use of high resolution sensors for scene detection and subject recognition, and the A6000 is a great example of this.