Flying home from the East, I usually honor crossing the Mississippi as the occasion for my first double dry martini, which means that passing the Hundredth Meridian, equidistant between the towns of Kearney and North Platte, Nebraska, is generally the cause for celebrating with the second. For at least a century and a half, the Hundredth has been the line of demarcation between the Eastern and Western portions of the United States, the meteorological instant at which the polite old East expires and the Wild West lunges forward. In the days of prop and turbo-prop planes, the Hundredth also coincided roughly with the start of the perceptible upward sweep of the continent, climaxing in an orogenic burst of snowy granite as the aircraft bumped and scraped over the ragged Front Range of the Rocky Mountains. Experienced at ground level, the geographical transition from East to West is less dramatic, essentially a matter of increasing aridity rather than of elevational rise. Still, somewhere east of Scottsbluff the Nebraskan Sandhills provide enough lift that the native Westerner, taking note of the depleted ozone, thinning air, snow squalls (in June), and—especially—the ubiquitous odoriferous sagebrush, long before he catches sight of Chimney Rock above the North Platte River perceives that he is almost home again.
On a morning flight last fall from Salt Lake City to Chicago, the view off the left wing over Evanston, Wyoming,...