"The Last Flight" is the 18th episode of The Twilight Zone and was first broadcast in February of 1960. It was written by Richard Matheson, and starred Kenneth Haigh and Simon Scott, with additional roles by British stage actor Robert Warwick and a man famous for recording the King James Bible, Alexander Scourby.
"The Last Flight" is a time travel story, and is one of the first in the series to explore that ground. ("Walking Distance" is a time travel story, but its mood is more of magical realism and exploring a dream than a story like this). A World War I pilot lands at a NATO air base in the 1950s, and learns that it is about to be visited by an old friend of his: a man who saved Britain in World War II, but that the pilot admits he let die in an act of cowardice in World War I. To make history go right, he must confront his inner character and make a decision about what type of person he is.
Twilight Zone episodes vary on a spectrum between magical realism and hard science fiction. Although this episode does take into account the emotions and thoughts of the characters, it is overall just a presentation of how a time loop can change history. Characterization takes a back seat to plot. And while the execution is not extraordinary, it was (as far as I could guess), the first appearance on television of a plot exploring the idea of time loops in science-fiction: a vein that would later be richly mined in Star Trek, Babylon 5, and other shows.
Another interesting point is that for me, viewing this show in 2014, World War I biplanes seem as archaic and distant as a cavalry charge: but upon doing a small bit of math, I realized that for the viewers of this show, World War I aviation would have been within memory of much of the audience: a World War I biplanes were actually only as removed from 1960 as an F-15 Eagle is to me.