Oh, we are slowly approaching the year of my birth. :) I didn't understand about the earphones. How was music played on a plane back then? I mean what is "pneumatic earphones" ?
By the way, I added your blog link to the standard footer of all my posts ;)
(;-)
The music was distributed through small pipes as sound. You would choose a channel and that would select a couple of pipes. The "pneumatic earphones: were made of two pipes, on for each ear, and you would listen to the sound through these pipes. No electronic in the distribution of sound.
Thank you, I guess.