From American Studies at the University of Virginia's Covering the War section of Urban and Urbane: The New Yorker Magazine in the 1930s:
[E]ven preoccupied with the thoughts of death, honor, and heroism that doubtless passed through the heads of millions of American soldiers on the eve of battle, the young man cannot resist the natural beauty of the full moon on a clear night. The image also plays with the sharp contrast between the plane, the latest in American technology, and the vast emptiness of the sky. It makes a subtle yet present commentary on the just how much technology has still yet to do.
The depiction also stands in stark contrast to that other famous poem of the war, Jarrell's "The Death of the Ball Turret Gunner." The illustration appears on the cover of August 22nd, 1942 issue of The New Yorker (full size), and is by the Russian-American artist, Constantin Alajalov.
A print of Alajalov's cover is available from The Cartoon Bank. (Via Kottke.)