Some text from here:
http://www.planetside2.com/news/lightassaultcommlink
No soldier on Auraxis causes more chaos and confusion on the battlefield than the Light Assault. Agile and deadly, they serve their empire as an excellent flanker and skirmisher. While other classes find themselves confined by walls, buildings, and sniper alleys, the Light Assault makes shortcuts and controls the flow of combat from on high. The battlefield is their playground!
The Light Assault’s extreme mobility is their defining trait and allows them to move faster than most other soldiers. Each one of the Light Assault’s various Jumpjet configurations grants them the ability to take on different obstacles, shifting their role in combat. The Standard Jumpjets allow them to make their way over barriers and enemy’s heads alike. They can also equip more specialized configurations, such as the high boost Icarus Jumpjets, to reach walled objectives and perched Infiltrators, or the hovering Glider Jets, to descend on vulnerable ground targets safely.
The Light Assault also excels at supporting their empire through their unique class grenades. The blinding Flash grenades can render entire squads helpless and allow for a momentary break in defenses. They also have access to Smoke grenades, which can be used to block sniper alleys and direct the flow of combat. Both of the Light Assault’s class explosives are important in allowing their empire to make the final push in capturing difficult objectives.
In addition to their utility on the field, they also excel at short to medium range combat. The Light Assault is able to choose from a diverse arsenal of various weapon types, including rifles, shotguns, and SMGs. These options allow them to adapt to whatever their environment demands. The best Light Assault soldiers make sure to use their powerful weapons with the element of surprise, disabling enemies before they know what hit them.
Though not as sturdy as other soldiers, the agile Light Assault can do serious damage when flanking enemy squads, taking advantage of both their vast weapon and support options. Whether acting alone to disrupt enemy forces or in a group to finish capturing a facility, the Light Assault is a fearsome presence on the battlefields of Auraxis.