Deltathor

The third strongest enemy among the Aircraft-type enemies, the Deltathor has a large difference in stats when compared to the Balthazaar. However, while it lost the capacity to heal itself, it also gained the Homing Shot attack, and the Mega Cannon Lv. 1 Stored Attack. Despite having rather high stats, it shouldn't be much problem as long as you pay attention to Guarding your Reyvateil.