As a result of the reduced capacity, Northwest is removing a combination of 14 B757s and Airbus narrowbody aircraft from the fleet.
In addition, the DC-9 fleet will be reduced from 94 aircraft at the start of 2008 to 61 aircraft (20 DC9-30s and 41 DC9-40s/50s) by year-end. [Emphasis added.]
The DC-9s have been overdue for retirement for some time, so that part of the reduction makes sense enough. Parking the Airbuses, not so much when there are DC-9s still to retire. While they are a bit big compared to the DC-9-50 (to the tune of around 25 seats; the A319 is the direct substitute in terms of seating capacity), the cost statistics via NWA’s latest filings with the DOT indicate that the A320 is cheaper to fly than any DC-9 in flying operations expenses. Significantly, fuel issuance is considerably less for the bigger and heavier A320 even versus the 105-seat DC-9-30 (937 gallons/hour vs. 1039-1215 [*]). Plus, you know, there are more seats to sell (or offer someone an empty middle seat, remember those?).
Maybe there’s something about the particular planes they want to park (that isn’t also something about the ancient DC-9s)? Otherwise, it looks like someone has their head up a fleet planning model.
[*] Note the decarbonization potential from replacing the relatively aged domestic airline fleet.