Songfacts®:

• In this early Rolling Stones song, Mick Jagger gets a bad case of wanderlust and buys a ticket on Flight 505. He doesn't know where he's going, and doesn't really care - he just needs to get away.
• At the end of this song, it sounds like the plane doesn't reach its destination, possibly going down in a crash.
  
  The common misinterpretation of this song is that Flight 505 was the plane crash that killed Buddy Holly, Ritchie Valens, and The Big Bopper in 1959, but this is not true. It is not officially confirmed by a news source that the plane crash of "The Day the Music Died" was actually flight #505. In any case, the lyrics to this Rolling Stones song have the line "He put the plane down in the sea," which of course, couldn't mean the Holly/Valens/Bopper crash that happened on dry land in Mason City, Iowa in 1959:
  
  Here is a fact page on the crash site, dry land, no sea.
  
  Here is the full text of the Civil Aeronautics Board Aircraft Accident Report on the plane crash that killed Buddy Holly, Ritchie Valens and the Big Bopper, loaded with minute details down to tachometer readings and altimeter settings, and there's no flight number mentioned there either.
  
  In any case, a flight heading from Mason City, Iowa, to Moorhead, Minnesota would have been a northbound flight, and northbound flights are traditionally assigned even numbers.
  
  Finally, this was a private chartered flight, not a commercial flight. So it's unlikely that an official flight number would have been assigned. Sometimes small aircraft use their plane's serial ID for the flight number; in this case, the plane's ID ("tail number") was "N3794N."
  
  So it looks like the "flight 505 = Buddy Holly's crash" thing is an urban legend. But a quick "buddy holly flight 505" search will show that this is a widely circulated rumor on the web.
• Flight 505 was also coincidentally the flight number of the BOAC (British Airways) plane the Stones took on their first trip to the US in 1964 (according to Bill Wyman, Stone Alone). >>

  Suggestion credit:
  Louie - Middletown, NY
• That's Ian Stewart on piano. Stewart, one of the founding members of the Stones, later left the group's lineup but stayed on as road manager until his demise from heart attack in 1985. Keith Richards would later say in his autobiography Life that he still considered The Rolling Stones to be Ian Stewart's band.
• The cover art for "Flight 505"'s album Aftermath has the Stones dressed and posed in suspiciously Beatles-like style; compare the cover work for Beatles For Sale and With The Beatles, and you'll see the importance of packaging when marketing a British group in the States. Aftermath was also the first Stones album recorded entirely in the US.