Boeing and Southwest Airlines today celebrated the 5,000th 737 to come off the production line as thousands of Boeing employees and special guests attended an historic delivery ceremony at the company's Renton, Wash., manufacturing facility. The 5,000th 737, a 737-700 painted in Southwest Airlines colors, was the centerpiece of the celebration. With more than 4,100 airplanes in service, the 737 represents more than a quarter of the total worldwide fleet of large commercial jets flying today. More than 541 operators fly 737s into more than 1,200 cities in 190 countries.