Character Analysis
The Personnel Officer hires Travis to work as a cabbie. At first, he's kind of suspicious of Travis and chides him for joking around when Travis says that his driving record is "clean, real clean—like my conscience."
However, when Travis says that he used to be in the Marines (and, implicitly, in the Vietnam War) the officer's attitude towards him changes since he used to be a Marine too. This shared experience and sudden bond of comradeship might have even played a role in landing Travis his job.