Sorry to all for the thread-drift. My real intent was to show the origin of the "Fifi" moniker.

Guppy:

I believe the origin here is that if all the airliners were fish, it was the littlest fish in the sea.

No conspiracy.

My Dad worked at Western. There, it was referred to as "Fat Albert," or "Fat Al." The character immortalized by Bill Cosby was quite popular when the 737 made its public introduction, so the name was a logical consequence.

Due to a common fuselage diameter with the other Boeings, and shorter length, it appeared to be "fat" due to fineness-ratio.

Anyone else have popularized names for the 737 at other airlines?