From a distance there isn't much difference. Same wing, same fuselage, 3 engines, etc.

The MD11 was Micky D's answer to high fuel prices in the late 1980's, early 1990's. Rather than spend the money to design, build and certify a "new" airplane, from scratch, they took the DC10 and "Modified" it. That included adding all the Computers for navigation and they eliminated the Flight Engineer possition by adding more computers to run the Hydrolic, Fuel, Pneumatic and Electrical systems, as well as checklists for abnormal ops.

They hung new engines on it, added those funky wingtips to reduce drag, added bigger fuel tanks and a center landing gear for the increased gross wt. They tried to do it on the Cheap and it was kind of a mess, a mix of old and new, a compromise, not a real solution and it was a pig when you flew it heavy, same wing as a DC10 but they added 100,000lbs. to the max takeoff wt.

They did the same thing with the DC9; put Flight Management System (FMS) computers in it and new engines, called it the MD80 series. I flew the MD88 for a year, it was a mess too, you could never take your eye off it, you never knew what it was going to do next!

The MD 11 had pretty long range (16+ hours with aux. fuel tanks in the cargo hold) but it did not meet the "fuel burn" numbers MD had promised to American, Delta and Swiss Air, who were the first customers. There were lawsuits over who would pay for the extra fuel, etc. I think American Airlines got some money out of them.

Long story short, they are mostly freighters now that the 777 has come along. Boeing bought McDonald Douglas years ago and pretty much killed off the MD 11 production line.

The DC10 was a great airplane in it's day, as was the DC9, and the 727, but it was a "Different Time" ie. fuel was a lot cheaper back in the 1970's! As the price of fuel went up, demand for more fuel efficient airplanes drove those older airplanes out of existance.

Everyone loved the 727, I only got to fly copilot on it for about 2 years, then I went to the 757/767, but it was a lot of fun to fly. The autopilot sucked, so you HAD to hand fly it a lot, which I loved. When I got on the MD11, I would hand fly it a lot too, but some of the Captains didn't like me to do that.

One Capt. said to me, when I clicked off the autopilot and auto-throttles, "You realize you have just removed two layers of Safety?!"

I said, "Yeah, well, I'm just going to pretend it's an airplane, and pretend I'm a Pilot, and I'm just going to fly it..." so you KNOW I had to grease it on or suffer the wrath. Luckily the wind was calm and it was a good landing, so good some of the Flight Attendants came up to the **** and asked, "Who made that landing, that was Great!"

Of course I've had a few go -not so smooth- too, but it's nice when you really -need- to get a good one, and you do!