“Neil” was folksinger Fred Neil, who wrote “the Other Side of This Life”, which the Airplane frequently covered in concert (it appears on their live album “Bless It’s Pointed Little Head” and is the song they’re singing during their infamous altercation with the Hells Angels in the Altamont doc “Gimme Shelter.”)
He also was one of the more strident anti-authoritarian voices from the early 60s and originated the “Up Against the Wall, Motherfuckers!” slogan that the Airplane incorporated into their anthem “We Can Be Together.”
Winnie the Pooh and Neil were the heroes of Paul Kantner (composer of both “Pooneil” songs.) He seemed to consider the two yin-yang opposites - Pooh symbolizing childlike innocence and wonder, and Neil representing adult sophistication and angry attitude. The songs also reflect that duality - one song (Ballad) being about the joy of discovery & experiencing magic, the other song (House) being a bitter, misanthropic rant against mankind’s warlike nature.