terminal building to be attached to "airline wings" (concourses), each providing space for gates and planes. (Pre-war airport designs had favored ever-larger single terminals, exemplified by Berlin's Tempelhof.) Burke's design also included underground refueling, direct highway access to the front of terminals, and direct rail access from downtown, all of which are utilized at airports worldwide today. O'Hare was the site of the world's first jet bridge in 1958, and successfully adapted slip form paving, developed for the nation's new Interstate highway system, for seamless concrete runways. In 1949 the City renamed the facility O'Hare Airport to honor Edward "Butch" O'Hare, the U.S. Navy's first flying ace and Medal of Honor recipient in World War II. Its IATA code (ORD) remained unchanged, however, resulting in O'Hare being one of the few IATA codes bearing no connection to the airport's name or metropolitan area. Arrival of passenger service and subsequent growth Scheduled passenger service began in 1955, but growth was slow at first. Although Chicago had invested over $25 million in O'Hare, Midway remained the world's busiest airport and airlines were reluctant to move until highway access and other improvements were completed. The April 1957 Official Airline Guide listed 36 weekday departures from O'Hare, while Midway had 414. Improvements began to attract the airlines: O'Hare's first international terminal opened in August 1958, and by April 1959 the airport had expanded to with new hangars, terminals, parking and other facilities. The expressway link to downtown Chicago, now known as the Kennedy Expressway, was completed in 1960. And new Terminals2 and3, designed by C. F. Murphy and Associates, opened on January 1, 1962. The biggest factor driving the airlines from Midway to O'Hare was the jet airliner; the first scheduled jet at O'Hare was an American 707 from New York to Chicago to San Francisco on March 22, 1959. One-mile-square (1.6-kilometer-square) Midway had no space for the runways that 707s and DC-8s required. Airlines had been reluctant to move to O'Hare, but they naturally did not want to split their operations: in July 1962, the last fixed-wing scheduled airline flight in Chicago moved from Midway to O'Hare. Until United returned in July 1964, Midway's only scheduled airline was Chicago Helicopter Airways. The arrival of Midway's traffic quickly made O'Hare the world's busiest airport, serving 10 million passengers annually. Within two years, that number would double, with Chicagoans boasting that more people passed through