A birthday honor? Doubtful. I'm still thinking that the flyover is a tribute to a graduating class at the Academy or a funeral for a noteworthy officer of high rank. Kirk played a major role in the defeat of Nero and the Narada in the Battle of Earth and he's a hero....but I don't think birthdays warrant this kind of gathering and a full-blown flyover. He's not an Earth or Federation head of state or government or another dignitary.
3 years from cadet to captain of the flagship... just saying...