The "Battle of the Planets" English adaptation refers to it as "Sonic Jet".
Performance and Functions
G-1 is capable of reaching Mach 4 speeds. By docking into the tail of the God Phoenix, it allows the giant craft to gain a verticle stabilizer tail for more stable flight while also serving as an accessory. Initially it had no built-in weaponry until episode 68 where it was equipped with twin heat rays.
In the OVA, the G-1 was redesigned with a more modern look. In civilian mode, it is an old red prop plane with two slanted vertical stabilizers and a jet intake. When it is transformed by the G-Bracelet, it becomes a blue and white high speed jet with red variable weep wings and is armed with laser guns.