In Greek mythology, Icarus succeeded in flying, with wings made by his father Daedalus, using feathers secured with wax. Ignoring his father's warnings, Icarus chose to fly too close to the sun, melting the wax, and fell into the sea and drowned. His legs can be seen in the water just below the ship. The sun, already half-set on the horizon, is a long way away; the flight did not reach anywhere near it.
The ploughman, shepherd and angler are mentioned in Ovid's account of the legend; they are: "astonished and think to see gods approaching them through the aether", which is not entirely the impression given in the painting. The shepherd gazing into the air, away from the ship, may be explained by another version of the composition; in the original work there was probably also a figure of Daedalus in the sky to the left, at which he stares. There is also a Flemish proverb (of the sort imaged in other works by Bruegel): "And the farmer continued to plough..." (En de boer ... hij ploegde voort") pointing out the ignorance of people to fellow men's suffering. The painting may, as Auden's poem suggests, depict humankind's indifference to suffering by highlighting the ordinary events which continue to occur, despite the unobserved death of Icarus.
Though landscape paintings with the title subject represented by small figures in the distance were an established type in Early Netherlandish painting, pioneered by Joachim Patiner, to have a much larger unrelated "genre" figure in the foreground is original and represents something of a blow against the emerging hierarchy of genres. --Wiki