MD-88 And MD-90: Why Delta Was Key To The Mad Dog

Delta had 185 MD-88s and MD-90s, whose retirement was accelerated to June 2020 because of the pandemic. With virtually eight in ten seats since 2006, Delta was utterly vital for both Mad Dog variants. We look back at how it used them.

Delta MD-90
This MD-90, N945DN, was ex-Japan Airlines and Delta operated it between 2012-2019. It is stored at Blytheville, Arkansas. Photo: Tomás Del Coro via Flickr.

Delta’s MD-88s and -90s

Delta operated 120 MD-88s in all, each in a 149-seat configuration comprising 108 seats in economy, 25 in Comfort+, and 16 in first. It also had 65 MD-90s, each with 158 seats, with the same number in first and Comfort+ but 117 in economy. The first MD-90 (registered N902DA) arrived in February 1995.

Unlike its MD-88s, Delta found that its MD-90s were significantly more fuel-efficient while being relatively quiet – in that era, anyway – and having superior hot-and-high airfield performance. And its larger capacity helped to reduce seat-mile costs. These characteristics enabled more flexible use of this series, although it ditched more examples for the B737-800.

Delta retired the last of its Mad Dogs on June 2nd, 2020. It was an end of an era, especially for the MD-90, no longer used commercially. On that final day, the last MD-88 flight (flight number DL88) was scheduled to arrive in Atlanta at 08:55 from Washington Dulles, while the final MD-90 service (DL90) was three minutes later from Houston Intercontinental.

Delta Air Lines McDonnell Douglas MD-88 N904DE (1)
Atlanta was crucial to the MD-88/90. Photo: Photo: Vincenzo Pace | Simple Flying

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Overwhelmingly the world’s #1 operator

Between 2006 and 2020, Delta had 386 million seats for sale by the MD-88 and 133 million by the larger -90, based on analyzing schedules information obtained from OAG. When combined, the airline had 519 million and a 79% share of the available capacity by all operators of the two variants. Saudia was next with just 5.2%, although it had only MD-90s.

In the figure below, you see that the use of the MD-90 grew strongly from 2011 and 2012, the consequence of acquiring additional aircraft from China Southern, Japan Airlines, and others. You can also see the use was reduced from 2017/2018, coinciding with aircraft beginning to be retired. The writing, as they say, was very much on the wall.

Delta's use of the MD-88 and MD-90
Between 2006 and 2020, Delta had over half a billion seats for sale by the MD-88/90. Source: OAG.

487 routes saw them

Between 2004 and 2020, some 146 airports saw Delta’s MD-88s, while the higher-density alternative was used to 125. Atlanta was utterly essential for both, but especially the MD-88, with around 324 million of its 386 million seats, OAG reveals.

Delta used the MD-90 on longer routes averaging 732 miles, a difference of more than one-quarter over its smaller sibling. While both variants’ top-10 routes were from Atlanta, the importance of the -90 on more demanded airport-pairs is clear to see, as follows.

  1. Atlanta-Washington National: the most MD-90 seats between 2004-2020
  2. Atlanta-Denver
  3. Atlanta-Philadelphia
  4. Atlanta-Minneapolis
  5. Atlanta-Baltimore
  6. Atlanta-Tampa
  7. Atlanta-St Louis
  8. Atlanta-Kansas City
  9. Atlanta-Milwaukee
  10. Atlanta-Indianapolis

In 2021, capacity by the A321ceo and B737-900ER on these above 10 has increased to two-thirds, up from less than half two years ago. These aircraft are vital to replacing the Mad Dogs.

What are your experiences or memories of flying the rear-engine variants? Let us know in the comments.