hahahaha....Delta is getting a Bang for their Buck....they said Delta planned on getting Rid of their aging 747 fleet....I'm sure they will convert them to cargo or sell them
Delta still flies (116) MD-88, (65) MD-90, and (91) 717. These are airplanes derived from the DC-9, which first flew in 1965. The MD-88's are
twenty-nine years old!. Cycles (one takeoff and landing) are what count regarding aircraft age and you can keep an aircraft running for very a long time (see third world counties), but usually after thirty years the "C" checks become prohibitively expensive and so do the repairs and corrosion they discover.
The aircraft in Aloha Airlines flight 243 accident was a (737-200) that had 89,000 cycles (the most in their fleet) with
19 years of service. The 737-200 was designed for 75,000 cycles but inspections and repairs can keep aicraft fuselages flying indefinitely.