Regular bow can use rockets to fire

Rockets will be used instead of arrows when using a bow

Having rockets & arrows in my inventory, I expected the arrows would fire

since the rockets where first in line, they were used instead on my bow (not a crossbow mind you)

Using the /give command to give rockets with no NBT data (not tested with traditional rockets) to the player
& then have the player fire a bow, the bow will fire despite having 0 arrows in their inventory
(side note, the firework counter WILL go down, and you can retrieve the "arrow" you fired and it will go back into your inventory as an actual arrow)