Because of its association with the entertainment industry, the Los Angeles area in the 1990s grew in importance as a center for multimedia production. The Los Angeles metropolitan area is a hub of the transportation industry, including automobile, aircraft, and aerospace production. However, in the early 1990s aerospace manufacturing suffered a sharp downturn as federal expenditures for military aircraft decreased, diminishing the industry's relative importance. The city is also a major supplier of fresh-cut flowers and contains the headquarters of many large corporations, research and development facilities, and financial institutions. The city has also become the financial gateway between Asia and the United States.
Tourism is an important part of the city's economy.
Los Angeles is dependent upon its extensive freeway system for transportation, and the roadways themselves have become closely identified with the city. With one automobile for every two city residents, the freeway system is often clogged with traffic. Smog from automobile exhaust and other sources is an intermittent pollution problem. The city is taking measures to lessen its dependence on freeway travel. Metrolink, a commuter rail line, operates six lines connecting the region's cities.