The Second Shell by Jack Williamson

The little Camel-back plane was a wonder. The soft whispering hum of the turbine engine belied its tremendous power. The slender, white metal wings cut the air at the rate of two and a half miles per minute. Presently we saw a smudge of smoke where the blue sea met the bluer sky ahead, and soon the little machine had dropped on the deck of a destroyer.

The sister vessel was four or five miles to starboard. The two ships were plowing deliberately along, at about ten knots, keeping some twenty-five miles behind the tramp steamer they were shadowing. One of the officers took us up on the little bridge, and we learned that the little ships were keeping track of the tramp with their radio equipment.