The on-sale date is from the publication date recorded in the Catalog of Copyright Entries, Third Series, Vol. 2, Part 2, No. 1, Periodicals, January-June 1948.
Captain Midnight [Captain Jim "Red" Albright]; Ichabod "Icky" Mudd; un-named Los Angeles science Professor; un-named U.S. Army General; Dr. Osmosis [also as Professor Graves] (villain); Osmosis' gang [Karl; other un-named] (villains, both die)
Synopsis
Mysterious sightings of flying saucers, especially in California, where the saucers appear to be much larger than in the rest of the country, and an explosion of one causing serious fatalities, spurs Captain Albright to investigate. He discovers that the "saucers" are radio-controlled discs that are radioactive and highly explosive, and that Dr. Osmosis is behind them.
The last 1/3 of page 9 is titled "U.S. Army Insignia: Aviation Badges", and illustrates six different wings: Command Pilot, Senior Pilot; Observer, Bombardier, Pilot, and Navigator.