WASHINGTON — They haven’t yet sat down for an interview. But they almost met at Gate 35X.

Donald Trump Jr., in a camouflage hat and in the middle of a phone call, leaned against a wall on Friday while standing in line at Reagan National Airport. And there, only feet away, seated and absorbed in a newspaper, was Robert S. Mueller III, the special counsel investigating Russian interference in the 2016 election, or what President Trump calls a “WITCH HUNT.”

It is unclear where the two men were headed, or if they even ended up on the same flight. And it is unclear if they ever made eye contact.

A spokesman for the special counsel’s office said Mr. Mueller was unaware of Donald Trump Jr.’s presence and had no interaction with him.

But just the sight of the men within each other’s periphery, captured Friday morning in a photograph sent to Politico, was enough to send the political world (and the internet) buzzing about the possibilities of what could have been said.