I notice that all of the covers shown here:
[url=https://ausreprints.net/cover/series/4405/16775/1/200/100]https://ausreprints.net/cover/series/4405/16775/1/200/100[/url] portray the Blue Ghost as translucent like an actual ghost, and the cover of #21 actually shows bullets passing through his body as it he were indeed incorporeal or ectoplasmic. But in the story in this issue, at least, he seems like a perfectly ordinary costumed vigilante with no actual superpowers whatsoever, looking a bit like a Ku Klux Klansman (apart from the cover, we must IMAGINE that he's blue).
Link to the book:
Invisible Avenger 17