In the third major section of Gulliver's Travels, Swift sends his satiric protagonist on yet another journey. One would think Gulliver would have had enough, and indeed his wife takes some convincing that he should be allowed to leave.
In this journey, it takes not long for Gulliver to be once again waylaid and sent on his way to a fantastic land. Instead of trying to satirize by throwing him among people of vastly differing size, as in the first two parts, the voyages to Lilliput and Brobdingnag respectively, Swift sends Gulliver instead to a place where the people are radically different not in size but in mind.
(The illustrator of the 1947 Crown edition adds an interesting interpretation to the target of the satirical references of Brobdingnag and Lilliput, and I have a discussion of their sounds as well.)
The Laputans are a strong parody of the environment in which Swift no doubt often found himself: the company of academics, those who spend all their time thinking in abstraction and no time working in practicality. The Laputans pride themselves in their fascination with abstract geometry and "the music of the spheres," the geometry of astronomy, but seem to be out of contact with simple practical geometry, because "their Houses are very ill built, the Walls bevil ['bevel,' i.e. crooked], without one right Angle in any Apartment; and this Defect ariseth from the Contempt they bear for practical Geometry; which they depsise as vulgar and mechanick, those Instructions they give being too refined for the Intellectuals of their Workmen; which occasions perpetual Mistakes."
Swift's allusion to (and derision of) academia goes farther and deeper: "They are very bad Reasoners, and vehemently given to Opposition, unless when they happen to be of the right Opinion, which is seldom their Case." Swift was friends with such people in real life: philosophers like Bishop George Berkelely, who argued that the material world was a fantasy of perception, for example, were long-time correspondents of Swift.
This attitude is perhaps the center of satire; that one must be close to the object of one's satire in order to create a penetrating caricature of it must be an axiom of satirical writing. In Abbott's Flatland, too, he is parodying the culture he is closest to, in the same spirit as Swift, writing a century and a half before. Swift spreads his venom across 300-plus pages, however, but Abbott manages to accomplish far more by leaving his story as a far shorter manuscript.
(I apologize for the curtness of this response; I was carried away by my sidetracks; see the earlier links above.)