You have to pick:

This would be fatal. There are many variants of the Boeing 747, but the 747-400 seems to be one of the more common ones. It has a dry mass of 178,800 kilograms. Dividing by ten years, that gives a consumption rate of 49 kilograms (108 pounds) per day.

Someone has actually consumed an airplane. It was Michel Lotito. However, he ate a 1,111 pound Cessna over 2 years. Apparently he typically ate 2 pounds of metal per day (although the math on the Cessna requires that he ate 3 pounds per day, so I guess it was a challenge for him). Anyway, this is nowhere near 108 pounds per day, so I guess even he couldn't handle a 747 in 10 years. Even for Michel, this feat would take roughly 360 years. And I'm pretty sure no-one is better at eating airplanes than him.

Some other information about Michel from the Telegraph:

His diet since 1966 included 18 bicycles, 15 supermarket trolleys, seven TV sets, six chandeliers, two beds, a pair of skis, a low-calorie Cessna light aircraft and a computer. He is said to have provided the only example in history of a coffin (handles and all) ending up inside a man. By October 1997, he had eaten nearly nine tons of metal

well I guess DDR it is!