Ladies and gentlemen, the McDonnell Douglas aircraft have left the air. Thank you.Yeah, they were as iconic as Elvis Presley. The MD-88 and MD-90 planes hold a revered place in aviation history and, as of today, Tuesday, June 2, they are no longer part of the flying lexicon. Affectionately known as the ‘Mad Dog’ planes, they took their final flight as part of Delta Air Lines’ fleet and now settle into retirement.The MD-88 had flown for 33 years; the MD-90 for 25. Delta expected to retire the twin-engine MD-88s at the end of this year and the MD-90s by the end of 2022, but CNBC reported that a sharp drop in travel demand has prompted the airline to idle more than 600 planes and retire some of its older jets early.Delta is the last U.S. airline to use those models after American Airlines retired its MD-80 fleet last year. The final two aircraft left Washington’s Dulles International Airport and Houston’s George Bush Intercontinental Airport, respectively, to fly to Delta’s home base in Atlanta.They will retire to the bucolic town of Blytheville, Arkansas.Delta said dozens of aviation enthusiasts, also affectionately known as ‘av-geeks,’ bought tickets to fly on the final flights.Noisy as all get-out, the McDonnell Douglas planes were nonetheless pioneers in the industry. The MD-90 was the last and final model and was notable for saving fuel and carrying a larger load while minimizing environmental impacts through less noise and reduced emissions, according to airlinegeeks.com. It also introduced such innovations as a redesigned and improved nose cone, 22-inch aisles, and an overhead handrail along the edge of the luggage bins for safety while walking through the aircraft.Delta owned 120 MD-88s and 65 MD-90s which flew a total of roughly 900 flights out of 3,000 per day. In Atlanta, the fleet accounted for almost half of all departures and arrivals. Let's block ads! (Why?)