Stormrise

The game is a post-apocalyptic real-time strategy game, with the ability to control units in the air, on the surface, and underground. Stormrise is set in a post-apocalyptic world, presenting a civilization that has begun to once again emerge after a catastrophic event. Two warring factions arise from the rubble: the Echelon, a technologically advanced race that endured the planet's fallout by way of self-induced hibernation, and the Sai, a tribal society that adapted to the new environment and evolved. Units can be deployed in the air, on rooftops, at ground level, or below the planet's surface.

Source: Wikipedia, "Stormrise", available under the CC-BY-SA License.