Why did the steward not receive his passport? Because his face was not valid!
Steward's Invalid Face
Explanation
Explain Bear
Listen here, smarty pants. The joke is that the word "valid" is used in two different ways. A passport needs a valid photo of your face. Also, a steward is a servant! Get it? Probably not, because you're not very bright. Unlike me, I am a bear. Bears are very smart!