Mellotron: I think I've read often enough that the guitar sound at the beginning of Bungalow Bill was a Mellotron, and maybe some other sounds as well (intro to Strawberry Fields?).
Moog: Heard clearly on Abbey Road (Here Comes the Sun maybe, by memory), and documented as being used there.
My question is: Which of the 5 (Beatles + GM) were the ones who "played" them? Or, especially for the Moog, did they get an outside "expert" to program it? I don't think those were exactly plug and play in those days, were they?
In other words, I could see John or Paul or George saying - "Cool sound, let's have some of that!", but who actually rolled up their sleeves and did the heavy lifting?
Wow - for once, honestly, I am probably the most-qaulified person in the world to answer this! So - nothing is known for sure on some things but... some if fairly well-accepted.
Chris Thomas plays the Mellotron parts on Bungalow Bill, but the guitar recording is of Eric Cook. Even the Beatles disagree on who played the Strawberry Filed intro - George says it was John, and he is heard playing almost the exact part on a Melodica in 1965. Paul plays it in Anthology, but he does not say it was himself - people just ASSUME because he plays it there. Flying - don't know. Mr Kite - don't know.
Moog - John does the wind noise on "I Want You" and Paul plays the solo on "Maxwell's Silver Hammer" (as I recall). Not sure who played on "Because" although pics of that day show John at the keyboard (among others!). "Here Comes the Sun" - I don't know.
"I don't know" is the normal answer for anything to do with Beatles parts, performances, or instruments! and it's the most accurate usually!