I think a great breakfast to have when you travel a lot might be eggs, toast, oatmeal, or maybe even a protein shake. These things can be eaten fast and also have health benefits.
Something fast but complete. When there's more time you can sit down and prepare something more elaborate like some scrambled eggs, but if you're in a hurry you can always carry with you a protein bar.
Depends on what you have available but from what I heard, a nice smoothie, or eggs could be a good option.
If by "travel often" you mean unable to sit down for anything then I think power bars or protein bars could be a very good fast and easy alternative.
I say a breakfast bar for me even tho I don’t work when I go to school I would bring a protein bar or breakfast bar to help me with breakfast