When I turned 10, Steve Ditko broke my heart by leaving Marvel and rejoining Charlton Comics, which published only two superheroes at that time. I loyally bought the new Blue Beetle (aquired from Fox Comics in the ’50s) and Captain Atom (whom Ditko had first drawn in 1960’s Space Adventures), but I no longer have them and I can’t remember whether they had any time travel in the ’60s. Nevertheless I know of a few possible time-travel moment in the ’60s Charlton superhero comics: the pre-Ditko Blue Beetle 2 (Sep 1964) features on its cover the Man of Dung vs. a mammoth and a saber-tooth tiger; Charlton Premiere 1 (Sep 1967), which (among other items) has Pat Boyette’s time traveling Spookman; and Hercules 9 (Feb 1969) with Thane of Bagarth vs a 21st century time traveler.
The mightiest man battles reds from today, and monsters from yesterday!

Variants

(1)
  1. “Charlton Comics,” |pending byline|, in Blue Beetle 2, September 1964.