Back to dinosaurs soon, I promise.
I've been doing some research on Nyctosaurus lately for my own web site and toward improving the Wikipedia article. The crest situation always confused me, because many traditional depictions of this pterosaur show it with a low, dorsal keel type crest on the snout, similar to some ctenochasmatoids. The well-preserved skulls of the famous gigantic-crested N. sp., however, don't show this feature, and neither to several other nyctosaur skulls. As it turns out, Chris Bennett, who has been working on a detailed osteology of Nyctosaurus, pointed out on the DML several years back that the "N. bonneri" style crest isn't real, an artifact of crushing mistaken for a crest and subsequently enhanced by preperators.
As for the Nyctosaurus sp. with the head like a sailing mast, older depictions showed it with the back-pointing boom much shorter than the up-pointing spar. However, the fossils of KJ1 and KJ2 (the crested specimens) appear to have broken booms, and Bennett 2003 states that the boom was at least 3/4 the length of the spar. Luckily this meme has taken off among paleoartists thanks to the efforts of Mark Witton, and John Conway updating his famously brilliant paintings of this species.
I've updated my own depiction here, as well as the version I had donated to Wikipedia. Oddly enough, I found the older version in a Flikr photo by mavra_chang accompanying a Nyctosaurus display at the Brazos Valley Museum of Natural History in Bryan, Texas. The version is CC licensed but that requires at least crediting my name somewhere. It's hard to tell if that happened there as the image is partially cropped, but they certainly didn't notify me or ask permission... Don't get me wrong, I'm stoked to have my stuff (however outdated) up in a frigging museum. Just, y'know, a heads up would have been nice.