Moonbeam, a fairy sitting on a mushroom, was sculpted as a small and simple tribute to the beauty and sensuality of nature, and as a result of John's sore feet after sculpting the monumental nine-foot Merlin. Not wanting to leave the realm of Celtic legend, but wishing to sculpt sitting down for a bit, Soderberg pursued his favorite image, the winged human form, in the Celtic world.
The winged human has always symbolized humanity's striving to rise above, to excel, to attain the spiritual or of spiritual intervention. To symbolically break the bonds of gravity is to symbolically break the mundane bonds of fear or failure or simple boredom.
But to have mental or spiritual wings does not imply a constant workaholic need to use them. It is also good to rest your wings, to sit back on the nearest mushroom and enjoy the simple beauty of a moonlit world.