Featuring a more modern design with cabin pressurization, the 240 series made some inroads as a commercial airliner, and had a long development cycle that produced various civil and military variants. Though reduced in numbers by attrition, various forms of the "Convairliners" continue to fly in the 21st century. \u00a0 \nTo meet the requirements of airlines for a pressurized airliner, Convair produced a revised design\u2014the Model 240. This had a longer but thinner fuselage than the Model 110, accommodating 40 passengers in the first pressurized, twin-engined airliner. The 240 first flew on March 16, 1947. \u00a0 \nThe Model 240 was followed by the Model 340, which had a longer fuselage, longer-span wings, and more powerful engines. The 340 first flew on October 5, 1951. In 1954, in an attempt to compete with turboprop-powered airliners like the Vickers Viscount, Convair produced the Model 440 Metropolitan, with more streamlined cowlings, new engine exhausts, and better cabin soundproofing. As the "Super 240" evolved into the CV-340 and CV-440, the design reached the limit of piston-engine performance, and future development centered on conversion to turboprop power. \u00a0 \nIn Australia, the Convairs were operated by TAA - CV-240, Ansett ANA CV-340 and CV-440, Airlines of NSW CV-440, Airlines of SA CV-440 and RAAF 2 x CV-440. \u00a0 \nFor more details of these and other variants, plus the very long list of civil and military operators, click here. \u00a0 \nThe specifications below are for the CV-440.