My next match-up discovery is of the historical Lakota single trailer war bonnet from the National Museum of the American Indian, cat # 22/5200. Unfortunately, I have no further information about this bonnet, except that it was poped up in the 1948 photo featuring Eli Stover, a Creek Indian.
In terms of its construction this war bonnet is made of a non-standard skullcap with ear flaps. The eagle feathers of the crown have black-white covert eagle feathers at the base, and tipped with yellow fluffs and yellow horsehair tufts. There is a rather long row of white ermine tubes as side pendants, lined with the upper side of the browband. The beaded browband features three stepped triangles on a white background. A row of brass hawk bells runs along the top of the browband. The trailer of red cloth, backed and bordered with canvas, is embellished with a crest of eagle feathers, descending from larger to smaller feathers. IMHO, it looks more 1870s Cheyenne, rather than Sioux.