In StarCraft II, the Terran unit that transforms into a powerful flying fighter is the Viking.
The Viking is a Terran transformable vehicle. In Assault Mode it operates as a ground walker with anti-armor weapons; in Fighter Mode it becomes an aircraft designed to attack enemy air units. This dual role lets Terran players adapt the same production investment to changing battlefield conditions.
The Viking is not the same as the Banshee, which is a dedicated cloaking ground-attack aircraft. A Medivac transports and heals biological units, while a Raven provides support abilities and deployable technology. Because the Viking can switch modes, it is one of the clearest examples of StarCraft II's emphasis on flexible unit roles.