More Americans are beginning to hold off on booking flights, getting haircuts, building backyard pools and replacing old leaky roofs — in some of the new signs that the consumer engine of U.S. economic growth could be losing steam. Over the past several weeks, households had already cut back on big-ticket purchases because of soaring prices, but in a worrisome twist, data suggests consumers are also beginning to tap the brakes on dining out, vacation plans and even routine services like manicures, hair cuts and home-cleaning appointments. Business owners around the country say rising prices, dwindling savings and concerns of...