As a brand, the reasoning for Lincoln's continued existence is questionable. Nothing they currently produce is interesting in any measurable way. Lincoln was once the Cadillac of cars, now it's the Mitsubishi of luxury brands at best.

This wasn't always the case, as Lincoln is reminding us with this stunning auto show display. None of the cars on the show floor for Lincoln (yet) are newer than a 1961 Lincoln Continental, and the oldest goes back to the 1920s. "See," the cars scream, "we used to be great."

The implication is that they'll be yet great again, though we haven't seen the proof. Give Lincoln credit, however, in that they knew we'd be opining about how terrible their current lineup is and comparing it to the old. They knew we'd say they were once great and now are not. They knew all of it and went ahead with the display.

What are they launching here? A Tumblr account and… nothing else?

Besides the MD-90s, Delta is picking up the leases on 88 Boeing 717s with an average age of 11 years from Southwest Airlines Co. LUV +1.51% The discount king was so eager to shed the leases it inherited in its purchase of AirTran Airways that it took a $137 million charge to retrofit them for Delta. Yet even with the planes' higher fuel and maintenance costs, Delta figures it is saving at least $1 billion on the MD-90 purchases, compared with buying new planes, making them roughly 10% cheaper to operate per seat than new 737s. It won't say how much the 717s are saving, but its fleet strategy executive said he is "thrilled about the deal we got."

Another idea is that it is preferable to own planes rather than lease them "so when you hit softness or an economic downturn, you don't (have to) fly empty planes with high monthly payments," he said. Delta owns 75% of its fleet.*

Mr. Anderson learned this from experience. In the mid-1990s, cash-strapped Northwest decided—with input from McDonnell Douglas and aging-aircraft experts at the Federal Aviation Administration—to keep 183 DC-9s, then 25-years-old on average—flying until they turned 40. The company even went out and bought 40 more from other airlines. Around that time, Mr. Anderson was the head of technical and flight operations at Northwest.

Today, Delta's fleet is both old and complex. It has 10 different models in its 725-aircraft mainline fleet, and the fleet's average age was 16.6 years at the end of September. The last of its 19 DC-9s, which came from Northwest, clock in at more than 34 years old, and are expected to be put out to pasture in the next year or two.

This compares with an average fleet age of about 12 years for United Continental and US Airways. Southwest's fleet is 11-years-old on average while JetBlue Airways Corp.'s JBLU +0.40% planes are six years old. American Airlines has a 15-year-old fleet, but the company recently ordered 460 new aircraft.