This was written by a very young John Denver, who was then a member of the Chad Mitchell Trio before beginning his solo career in the 1970s. Denver wrote this in 1967 during a layover at Washington airport, "Not so much from feeling that way for someone, but from the longing of having someone to love."
The Chad Mitchell Trio recorded the song that year, as did Spanky & Our Gang and Peter, Paul and Mary. It only became a hit when the latter act covered the song again two years later.
On one of his BBC radio specials, John Denver said: "This is a very personal and very special song for me. It doesn't conjure up Boeing 707s or 747s for me as much as it does the simple scenes of leaving. Bags packed and standing by the front door, taxi pulling up in the early morning hours, the sound of a door closing behind you, and the thought of leaving someone that you care for very much. I was fortunate to have Peter, Paul and Mary record it and have it become a hit, but it still strikes a lonely and anguished chord in me, because the separation still continues, although not so long and not so often nowadays."
The 1969 hit version by Peter, Paul and Mary came at a great time for Denver, who had just disbanded the Chad Mitchell Trio. Denver became the senior member of the group when Joe Frazier and Mike Kobluk left (Denver replaced Chad Mitchell, chosen in an audition that drew about 300 singers), but had no name recognition. Some of his first solo appearances were billed as "John Denver, writer of 'Leaving On A Jet Plane'." Known for this song, Denver got some club appearances and TV gigs, which helped launch his career as one of the biggest-selling artists of the '70s.
Denver claimed that he wasn't a prolific or systematic songwriter - he wrote songs when they came to him. Some of his popular songs took months to complete, but this one took him just a few hours to finish.
This became the biggest hit for Peter, Paul and Mary, and also their last. The trio charted 12 times on the Top 40 from 1962-1969, scoring with their renditions of "Puff The Magic Dragon
" and "Blowin' In The Wind
John Denver successfully took legal action against New Order, claiming that the guitar break on New Order's third single from their Technique album, "Run 2," too closely resembled "Leaving on a Jet Plane." The case was settled out of court, and as a result the single can never be re-released in its original form.