Funny this article just popped up a couple days ago. https://www.telegraph.co.uk/travel/t...ll-in-service/

That article says the oldest DL plane is N905DL. It was one of DL first 8 orders of the MD aircraft, and actually started life as a MD-82! But is now a MD-88.

It's not that crazy that there are planes > 30 years old and still flying, but it does seem pretty wild to me that these planes have spent all 30+ years with the same airline.