Seems to be for all his live appearances - is this right? Any idea when it started, etc.? Was it just for such things as Carnegie Hall, Town Hall?
On the 3/72 "Creepy Stories" show, Shep does an ad for an upcoming live show at the Carlton Theatre in Red Bank, NJ on 4/7/72. It was done with a big fanfare and Shep mentions that it is being presented by Staggerwing Productions. (See Audio Link)
Staggerwing, on the other hand, is also a bi-plane made by Beechcraft.
With Shep's love of flying this may have been the inspiration for the name.
According to inside back flap of Leigh's book she was co-owner.