I just now realized, how the hell is Optimus able to constantly destroy Starscreams ass?! In reality Starscream should be two times bigger than any of the Autobots. I'm just pointing this out because I saw the picture on the homepage of the original 2007 cast all together.
Bayverse. That's all you need to know. EDIT: Actually, you're right. That F-22 is definitely WAAY BIGGER than the Peter Built. Sure, Optimus may be tall, but Screamer should be bigger, and wider.
According to scale charts and whatnot, Optimus is about 28 ft tall. Starscream is about 30-31 ft tall. With his legs extended he'd be even taller. While the F-22 is larger than the truck, the mass is displaced differently for each. Starscream has about a 3 ft height difference, and he is wider than Prime. The scene that comes to mind is the forest battle in ROTF. Just rewatch that scene and you'll see.