Board Thread:Modded Servers/@comment-29212992-20161030194141/@comment-29095449-20161128203202

If you read this section on the lotr wikia:

" In the book they are described as wearing a uniform of black robes and black surcoats, embroidered in white with a tree in blossom under a silver crown and many-pointed stars. Their helms were high-crowned and pointed, with long cheek-guards fitting to the face, and above these were set the white wings of sea-birds to honor their seafaring  Númenórean heritage; the helms were  Mithril  and heirlooms from ancient times. While they were Númenórean in design, they were not in origin. Few helms escaped the  Downfall, save perhaps those of  Elendil  (which became the White Crown),  Isildur  and  Anarion . Anarion's was crushed by a stone-cast from  Barad-dûr. "

Here you will see, that the wing on their helmets was to resemble sea-birds in order to honour their Númenorean ancestors. Again, not many helmets survived Númenorean times save a very few, meaning not much was known about them.