the 737-300 was brought into service in 1981. it was used by both us airways and southwest airlines. the 737-300 is the first model of the 737 classic series. the -300 can usually hold 128 passengers. the 737-300 series was made until 1999. the last -300 was delivered to air new zealand on 17 december 1999. this was the 1,113th 737-300 made.