Seisen Ren'ai Yuugi

Frontier planet "XIAN" far from the Earth. There are no planetary governments and the two major conglomerates of Ron and Zoroa dominate and prosper by free trade. Ryuta graduated from the military academy and came to Shan, the land of memories of his deceased father. He was welcomed by Ron Ron, the general commander of the army, and was invited to the Mayfa Corps Base, which is the headquarters. In the meantime president Ray Long suddenly dies. At the same time unknown identity enemies attack the base. Ryuta picks up three young ace pilot girls and tries to organize defense. From now on they are being swallowed by the war...

[From vndbreview]