flying
Explanation
The Joke
An uncle is talking to his young nephew, who is about to take his first international flight. The uncle tells him: "Wow! Your first international flight! Well, they're a bit more fancy than usual. For instance, if you want the stewardess to get you a drink, just write 'help me' on a piece of paper and hand it to her." The caption below reads: "I'm no longer allowed to speak to my nephew."
The uncle is deliberately giving terrible advice. If a child on an international flight hands a flight attendant a note reading "help me," the crew would almost certainly interpret it as a distress signal -- possibly indicating the child is being kidnapped or trafficked. This would trigger a serious security response, potentially involving the plane being diverted and the child's family being investigated.
The Humor
The humor lies in the gap between the uncle's casual, seemingly helpful tone and the catastrophic consequences his advice would actually produce. The punchline in the caption confirms that his "prank" did indeed cause serious problems, resulting in him being banned from contact with his nephew. The comic plays on the specific anxiety around child safety on flights and how seriously airlines take any indication of trafficking or abduction. It also fits the classic "terrible uncle" archetype -- the family member who thinks it is hilarious to give children dangerously misleading information.