The heyday for Ford's transport was relatively brief, lasting only until 1933, when more modern airliners began to appear. Rather than completely disappearing, the Trimotors gained an enviable reputation for durability with Ford ads in 1929 proclaiming, "No Ford plane has yet worn out in service." First being relegated to second- and third-tier airlines, the Trimotors continued to fly into the 1960s, with numerous examples being converted into cargo transports to further lengthen their careers, and when World War II began, the commercial versions were soon modified for military applications.