The 727 that Vanished (2010)
airspacemag.com
airspacemag.com
The article is dated September 2010. Flight MH370, a Boeing 777-200ER, that went missing in March 2014 is quite a bit larger in every dimension than N844AA, a Boeing 727-223.
Length and wingspan:
N844AA: 153x108ft or 47x33m [1]
MH370: 209x212ft or 64x65m [2]
[1] http://www.museumofflight.org/aircraft/boeing-727-223 [2] https://en.wikipedia.org/wiki/Boeing_777#Specifications
http://www.newsweek.com/pieces-mh370-found-reunion-island-36...
But since a trace of MH370 has indeed been found, I guess we should say that the title for "the largest aircraft ever to have disappeared without a trace" has reverted back to N844AA.