(I play with a controller, so don't know the keyboard buttons, maybe someone can help out with those in the comments).

If you have a mission to go somewhere, go into scanner mode and point your crosshairs at the mission icon, press A and you will see the option to press X to grav jump there, without using the menu. You can also use the function to grav jump to different systems, as long as you find them in scan mode.

The ability to take off from a planet and travel to another without using the menu helps a lot with immersion and feels nicer than interrupting your flow with the menu all the time.

I usually use the menu to select a mission, then travel in this seamless manner.