I had to maximize a new terminal window manually at the start, because it launched as a window, only covering part of my screen (it was slighly annoying.).
This behavior can be changed to open an already maximized window, by adding the following parameters to the command:
gnome-terminal --window --maximize
On Ubuntu, this can be changed in the keyboard settings, by disabling the default
Ctrl + Alt + T
combination to open a terminal window and creating a new one with the above command.