This was a sweet story with a lot of good details. I like the fact that the problematic coffee habit was a problem throughout the story, and that it was a lighthearted tale that saw good humor in a situation that could otherwise be quite annoying and scary (i.e., missing a flight because airport security found something concerning in your suitcase).

In the opening sentence, I think "again" would be better suited at the end of the sentence to create a more fluid read (i.e., "Rushing through the airport doors, I glance at my watch again."). There's also a typo in the opening paragraph ("I have told myself a million times, and everyone in my family, that I drink [too] much coffee."

My only big suggestion with the story is that it felt like the protagonist's reaction to finding the coffee can in his suitcase. Earlier in the story much is made about how late he was for the flight and how annoyed he was about it, which kind of undermines the idea that he would find anything about this funny if a potential missed flight is in the back of his mind. You might consider making the setup for the story a little less stressful for the character so that he's more open to finding humor in the situation.

The humor he finds in the situation also feels a bit over the top for what it is. This felt like a bit of a delivery problem, where the way he was laughing and had tears streaming down his face and couldn't control himself preceded the explanation, so the reader's expectations are set incredibly high that it's going to be truly hilarious, but then the reader gets the punchline and it's more amusing than laugh-out-loud funny. I'd recommend trying to reconcile those two things, either by downplaying the reaction a bit leading up to the explanation, or by increasing the amount of humor in the payoff.

Overall this was a fun and enjoyable read. Nice work!