Aerial refueling has been around since the early days of aviation, but it's still a fascinating idea.
Here's how it was done in 1923, courtesy of Wikimedia Commons:
Things have come a long way since then. Now, when fighter jets need to refill their tanks, they approach a KC-135 Stratotanker.
Once they're in range, the KC-135's "boomer," who lies on his stomach with his head supported by a chin rest, controls the flying boom — basically a tube — to get it into the fighter's fuel receptacle, according to the Aviationist.
Per the YouTube description, this video of the process was taken by Staff Sgt. Robert Barne. The boom operator appears at the 0:49 mark.