Angel is the highest-tier skill in the Wind Master skill tree. Hold ↑ or W (see: Controls) to activate the angel wings and start to glide through the map. While gliding, blue and white particles will trail behind you until you stop holding down ↑ or W. Note that while this does keep you from falling at normal speed; you will still slowly descend.
Also note that it sometimes won't activate the first time, make sure it's activated first before or you'll fall.
Shamans in Divine mode will have permanent angel wings while they are shaman; however these are decorative and they cannot use the skill unless they have upgraded it in the skill tree.