Andrew Oikonny is a very tall snow monkey, standing taller than even Wolf O'Donnell. He appears to have robotic limbs as seen in his character artwork for Star Fox: Assault, suggesting he once fell victim to an accident, or is a reference to the steel anklets that appeared to be worn by the original Star Fox cast.
It is interesting to note that when you confront Star Wolf in Venom, he wears some sort of macro-binoculars. He probably wears this due to eye damage after being defeated on Fichina. But in later games, he doesn't wear them. It's also possible that the macro-binoculars were simply necessary for him to pilot the Wolfen II.
Andrew's devotion to his uncle is evident in every one of his appearances as far as his statements about any enemy of Andross is an automatic enemy of his, and warnings about bowing down before the emperor, and even declaring in victory a score for his uncle at least once. For all his whining and boasting over his Uncle's authority, Oikonny seems to be an intelligent individual judging by the fact he can read books and is able to make military tactics and lead his rebellion using the typical methods of Andross's army. For all his limited experience at piloting, Oikonny seems to have developed his Uncle's strong tactical knowledge by using his Stealth Squadron at an unsuspecting moment, as well as revealing his flagship's secret transformation when he was cornered in the canyons on Fortuna, something the seasoned campaigner Peppy Hare knew to be conscious of. In addition, Oikonny's comments when directing his flagship to Fortuna when Star Fox was closing in on his ship implied that he was attempting to bait Star Fox into flying into a trap and then deal with them personally. Nevertheless, according to the official Star Fox 64 strategy guide, Oikonny is not much of a fighter or flyer, evident by how easily he is defeated in all his battles. But his overconfidence proved to be his downfall when he was caught monolouging when his flagship was shot down. The Lylat Wars Comic also portrays both Andrew and Pigma being extremely terrified of Andross when in his audience, facing his wrath of disapproval for their failure.
According to the Star Fox 64 Official Nintendo Player's Guide, Andrew Oikonny's favorite book is The Apes of Wrath, which is named after the novel Grapes of Wrath.
Both the Lylat Wars Comic depicted Oikonny being booted off from Star Wolf alongside Pigma because they disobeyed orders by Wolf O'Donnell via attempting to kill Fox McCloud and the other Star Fox members behind Wolf's back. The Assault instruction manual also supported the story of Oikonny being kicked out of Star Wolf, yet it is not directly stated in the game why he left Wolf's team or if it involved a similar incident with Pigma. According to his trophy Smash Bros. for Wii U, the reason given is that his boastful and arrogant attitude despite being being an unskilled pilot is what made Wolf kick him out of Star Wolf.
Like Leon, Oikonny's Japanese and English voices in Assault are very different. In the Japanese version, he has a high-pitched, somewhat crazed voice, while in the English version, his voice is goofy-sounding (low-pitched in Star Fox 64 and high-pitched in Star Fox: Assault).