A few things I kept in mind when designing Starscream is that he is in several iterations second in command, an air commander, egotistical, treacherous, ambitious, deceptive, pretty devious, kind of kind of freaky. 

The vehicle I chose for Starscream would be a jet that most closely resembles his Bayverse counterpart's F-22 Raptor fighter jet. While the vehicle may most closely resemble the Bayverse counterpart's jet, the color would be in reference to his G1 colors, but slightly altered to colder variations, such as changing red to pinkish red and a dark shade of purple that leans towards blue. I also darkened the white to be slightly gray, and the cockpit's window would retain its yellow color. 

When it came to color, I chose to use colder variations of the G1 colors to further differentiate the palette from other characters in the whole Transformers roster, as well as keep his shade of red from being too similar to the Autobots insignia's color. These sorts of changes were also done for Starscream's animated counterpart. Also, the distribution of color across Starscream's body is noticeably more diverse, filled with patterns, and takes up his body in abundance. This aspect of him reflects his flashy nature and sets him apart from the rest of his Decepticon peers. Considering his treacherous nature, Starscream is not fully loyal to the Decepticon cause, not loyal to a faction. He is loyal to only himself. 

When it came to his body, I gave Starscream a thin, lanky body filled with different gaps as well as thin and flat structures for his appendages. These particular parts of the body were meant to make him more aerodynamic in his robot mode, giving him efficient mobility in the sky and midair. The gaps allow air to pass through, reducing air resistance while moving through the sky. Kind of like the gaps between the wings of biplanes. The thin wide surface area of some of the body parts assist with midair steering, similar to the function of wings, rudders, and stabilizers found on most aircrafts. The upper arms are chain-like attached to a ball and socket joint, and the forearms are composed of these four adjustable flat panels with jet stabilizers sticking outward. These forearms conceal his tools as well as his null ray. I gave him long and large shoulder pads, kind of like Vegeta's shoulder pads over here. This particular design was meant to reflect Starscream's deceptive nature, as it's his attempt to seem more physically imposing than he actually seems without them. I also gave Starscream digitigrade legs like those of Earth's avians, which provide the advantage of better launching and shock absorption from landing. I placed his wings and thrusters on his back, his cockpit on the center of his torso, and the jet's air intake on his chest, like most of his iterations. 

When it came to his face, I wanted Starscream to look naturally devious, like he's got a resting, scheming face. I came up with something along the lines of a cat's face, especially the colon 3 cat emoticon, but evil. So, I gave him sharp eyes and a sharp W-shaped mouth that slightly protrudes outwards. Weirdly enough, I almost gave him a full bird beak, but I personally preferred the mouth. As for the helmet, the top mainly takes inspiration from his G1 counterpart, and I just added these triangular sides with the vents that reach around the head.