I made this animation in a morning. The vector illustrations took less than an hour each, and were converted into paths. After watching a few videos of birds in flight and flowers blooming, I animated the paths. I did cheat a little and use Illustrator Beta's new Turntable feature to generate a few frames of my bird, Pickle, to turn and face the sky before turning into a star (assuming that's what happens to pets when they pass on). Turntable is pretty decent if you know the basics of animation and use it more for references. A few effects later and it's ready!