This is a cover painting for Amazing Stories, August 1942, by Harold McCauley. The cover:
The ISFDB entry for this issue is here. I found both the painting and the cover at Pulp Covers, which also gives us a bonus back cover.
Either something in that description is missing, or this was a concept come up with someone who really doesn’t understand physics. You can download and read this issue from the Internet Archive.
A ramjet by any other name…
In a denser atmosphere, the aircraft is more buoyant and the jet probably works more effectively.
And, that’s one happy looking Uranian.
Of course, the details on page 238 show up all sorts of errors. Such as assuming that liquids can be compressed (they can’t!). And what kind of a creature is part-amphibian and part-land dwelling? An amphibian, that’s what!
I like the overstuffed easy chair at the pilot’ station the lady is manning.