The Boeing 737-300 was the first variant from the American aircraft manufacturer’s 737 Classic series to take to the skies, doing so in 1984 with USAir. Boeing’s data showed that it produced 1,113 of these aircraft, compared to 486 and 589 for the 737-400 and 737-500 models that made up the rest of the 737 Classic family. After 40 years of flight, let’s take a look at which airlines still fly this popular 737 variant.