Since this thread got corrupted earlier today...my original post vaporized.
>>> From the 2003 NWA 10K
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Excluding DC9 aircraft, the average age of Northwest operated aircraft is 10.7 years.
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Now, take into effect that over half the 742 fleet has been retired and the new 330's are on-line, this number will definately go down.
It's also worth noting that over 90% of the D9's are owned by NW and not leased. Therefore, they are probably making profits on running these planes that they wouldn't be if they had newer planes. Plus I'll take a FC seat on a D9 over a little seat on a CRJ any day of the week!