Pegasi

Pegasus ponies, often referred to as Pegasi, are ponies characterized by their wings and their ability to fly and manipulate clouds.

Traits
Pegasus ponies possess wings. They are capable of great speed in the air, though not always as fast as earth ponies on foot, as seen in Fall Weather Friends. While competing for the title of Iron Pony, Rainbow Dash is equally matched with Applejack, an earth pony, though several other pegasus ponies who participated in the Running of the Leaves are shown to be exhausted.

Pegasus ponies are seen manipulating the weather in several episodes, moving clouds to either cause a storm or clear the skies. In Sonic Rainboom, they also create snowflakes and rainbows in special factories.

Pegasus ponies have a unique ability among ponies to naturally walk on clouds, which is elaborated upon when Dash's friends wish to cheer her in the Best Young Flyer competition. This ability is not limited to pegasus ponies; Gilda, a griffon, is also seen walking on clouds, and in May the Best Pet Win, several other creatures capable of flight take seats on clouds.

Appearances
Pegasus ponies are mostly seen in Ponyville and Cloudsdale, the latter of which exclusively pegasi reside, and appear to be completely absent in the brief showing of Manehattan. Canterlot is almost devoid of pegasus ponies, with the exception of Celestia’s royal guards and, to an arguable degree, Celestia herself, along with Luna. The guards can be seen carrying her in a flying chariot in Swarm of the Century. Another pair of royal-guard pegasus ponies carry Twilight Sparkle in a similar chariot in the first episode.