After years of being outgunned by Japanese rivals, the American auto industry has made small cars a central part of its strategy, seeking to capitalize on a fundamental shift in the preferences of consumers in an era of fast-rising gas prices. By refocusing on small cars and de-emphasizing the gas-guzzlers that had long sustained the industry, General Motors and Ford in particular are preserving jobs and positioning themselves to prosper. Their efforts are already paying off in the marketplace, reported the New York Times newspaper Monday. Ford’s tiny Fiesta is the best-selling subcompact in the United States this year, and G.M.’s Chevrolet Cruze outsold every other compact car in America last month except the segment-leading Honda Civic. Nearly one in four vehicles sold in the United States in April was a compact or subcompact car, compared with one in eight a decade ago. Of the small cars sold in April, about 27 percent were American models, compared with 20 percent a year earlier. The emphasis on smaller vehicles has proven to be a necessity for the recovering auto companies. Rising fuel prices have prompted a steady migration away from bigger vehicles since the spring of 2008, when gas hit $3.50 a gallon. Industry analysts and company executives say the shift is likely a permanent one, as consumers flock to small cars packed with features like heated leather seats, Internet access and voice-activated entertainment systems.