BILL CRIDER'S POP CULTURE MAGAZINE
One of several handsome wraparound covers for IF when James Quinn was publishing it by the unfortunately-named, at least for his time, Ken Fagg. I'm not sure Fagg worked much for any other market in sf.
Looks like he did some Winston juvenile hardcover covers and then went on to work, or work some, primarily for the likes of HOLIDAY...he was probably a pretty close neighbor in upstate NY to Quinn, who was always very interested in how good his magazines looked (much moreso than, say, Robert Guinn, who bought IF and paired it with GALAXY at about the time HL Gold had to turn over editorial duties, if not yet on the masthead, to Frederik Pohl).
All his IF and Winston work clustered in the mid '50s. Seemed to like aviation subjects, which is perhaps why his spaceships all look like airplane fuselages.