Delta Air Lines parked its last Douglas DC-9 planes this week, ending a long, long history for the aircraft. Delta's DC-9s came as part of its 2008 marriage with Northwest Airlines, which loved the plane.
Northwest in the early 1990s decided it would be more profitable to update its aging DC-9s than spend the money to buy all-new ones. Although less fuel efficient than newer planes, the DC-9s were otherwise cheap, and a lot cheaper than buying replacement planes.
In fact, Northwest bought up DC-9s from other airlines as those airlines were modernising their fleets, adding to its own DC-9s. A bunch of Northwest's DC-9s came in its 1986 merger with Republic Airlines.
Northwest's total of DC-9s hit 180 in 1997 before it began retiring some of its oldest DC-9s. On December 31, 2007, the last year before the Delta merger, Northwest still had 94 of the planes, which at that time averaged 35.6 years old.
Since then, Delta has been paring down the DC-9 fleet, which stood at 16 as of September 30, 2013.
"The DC-9 has been a workhorse in our domestic fleet while providing a reliable customer experience," said Nat Pieper, Delta's vice president of fleet strategy. "The aircraft's retirement paves the way for newer, more efficient aircraft."
One of the new planes is the Boeing 717, which is really a 1990s-era update of the original 1960s design of the DC-9. Delta is picking up 88 Boeing 717s from Southwest Airlines. Southwest acquired the planes in its 2011 merger with AirTran Airways and then decided the 717 didn't fit into its plans.
Delta for 28 years had operated DC-9s, with the first DC-9 entering Delta's fleet in 1965. The plane had been gone from Delta's fleet since 1993, though, until Delta's merger with Northwest Airlines.
In 2013 the average age of the 16 DC-9s in Delta's fleet was 35.1 years.
The DC-9 was superseded by the McDonnell Douglas MD-80 models, which proved very popular. American Airlines at one time operated 300 of the various MD-80 models, and still had 179 in its fleet as of September 30. McDonnell Douglas then offered an updated version of the Dash-80, the MD-90, which did not sell so well.
McDonnell Douglas had a small version of the MD-80/MD-90 family under design, the MD-95, before it merged in 1997 with Boeing. Boeing subsequently renamed the MD-95 as the Boeing 717.
So much for the family tree.
Meanwhile, Delta has also announced it is verhauling the interior of many aircraft in its fleet, with enhancements that address passengers' desires for more space for carry-on bags and accommodation of their laptops, cellphones and other electronics.
The Atlanta-based airline said the improvements will be phased in starting in spring through 2016 at a cost of more than $US770 million ($A867 million).
Among the enhancements, dependent on model of aircraft: larger overhead bins, roomier bathrooms, electrical outlets at every seat, in-seat video screens, improved cabin lighting and seats with adjustable headrests.
Delta spokesman Paul Skrbec said that while he can "never say never," the airline has no plans to create fees for any of these improvements.
"The focus is not doing things to increase fees at this point," Skrbec said.
Since airlines first began charging for checked bags as a revenue source, many passengers have countered by bringing as much as possible on the aircraft with them. This strategy has strained demand on the overhead bin space and at times resulted in passengers being rebuffed moments before takeoff because their carry-on pieces were deemed too large.
Delta said in its announcement that it will soon become "the first carrier in North America to install the new bin system, which will increase passenger carry-on baggage capacity by more than 50 per cent."
Skrbec said that passenger feedback has been strongest for a place to plug in.
"Generally, our customers have been very clear that having access to power has been a priority for them," he said.
Twin Cities-based airline analyst Terry Trippler, of www.theplanerules.com believes Delta's announcement is "a direct result of Delta realising there is a third strong global airline now" among its competition, with the merger of American and US Airways last month. United is the other primary rival.