Both the command prompt and powershell can 'maximized', you must remember 'maximize' does not equal full screen. By default, they will both maximize to 80x25, which for me takes up the height of my screen, and about 1/3 the width. You can change this on either powershell or cmd by left clicking in the top left corner of their window, going to properties, then 'layout'.
If you go this route, I like to uncheck 'Let System Position' Window, and Position the window at 0,0 - the top left corner. It takes some practice to get the Window size perfect, it's based on 'lines' and not pixels, so what looks like full screen for your monitor, might be too big for your laptop, etc.