I am also looking for the jetplane sound.
Don't get lucky on PC3LE to set up a flanger sound changing LP cut off and resonance with LFO ???

Maybe I'm oversimplifying this, but I've been playing in a Beatles cover band for over 15 years, and I emulate the jet plane sounds in USSR with plain, old .wav files that I downloaded from various free SFX library sites on the 'net. Before I had my PC3K7, I played the .wav files back with a custom-built playback unit I triggered via MIDI, but now I just load the .wav files for this and many other Beatles SFX (like the alarm clock in A Day in the Life) right into my user sample memory. I create a program with a given song's SFX (I have four different jet sounds in USSR, plus I lifted that odd donkey-like sound in the beginning from one of the bootleg multitrack .mogg files using Audissey) then I assign each SFX to a single key (ignore release). I usually create a setup for a song with SFX and map the SFX trigger keys to unused keys - USSR, for example, would be piano over most of the keyboard with the SFX mapped to the five highest keys on the board.

I have the PC3 LE - so it doesnt load samples unfortunatley

I use the Rockey/Smile piano for everything Beatles.....also works for me on Toto-Hold the Line