its existing DC-9-50s.  Also designated DC-9 Super 80, this aircraft had been a more modernized version of the previous -- 50 series variant for medium-range deployment and featured a further fuselage stretch for still higher capacity and refanned, higher-thrust, and more fuel-efficient Pratt and Whitney JT8D-209 engines.  Austrian, which shared the distinction of being launch customer for the design with Swissair, inaugurated the first elongated DC-9-81 into service on October 26, 1980 on the Vienna-Zurich route with aircraft OE-LDR "Wien."  The twin-jet was later redesignated MD-81 and quickly became the short- to medium-range workhorse of its fleet. New additions to its ever-expanding route system included Larnaca in 1979; Jeddah, also in 1979; and Tripoli in 1981. Another 1980 milestone had been the foundation of Austrian Air Services (AAS), which would eventually become a wholly-owned subsidiary, to operate Austrian domestic routes with two 19-passenger, twin-turboprop Fairchild Swearingen Metro II commuter aircraft.  The first such service had been operated on April 1. The MD-81, intemittently proving itself to be as optimally suited to its route system as the twin-jet SE.210-VIR, the DC-9-30, and the DC-9-50 had been, was followed by its shorter-fuselage derivative, the MD-87, which Austrian ordered on December 19, 1984 for lower-capacity route sectors, and the Austrian Air Services fleet was equally upgraded with the addition of two 50-passenger Fokker F.50 twin-turboprops which were ordered on September 25 of the following year. 4. Transatlantic Return Operating a modern, fuel-efficient fleet over an expanding route system and carrying almost 1.5 million