Well, from what I have seen in the past 15 years, the 777's have replaced most of the 747's, all of the MD11's and DC10's, and all of the L10-11's. Boeing has shut down the 757 line, not sure about the 767 line, but who's buying new ones? Anyone? And they are stretching the 737 to replace those two (larger) airframes.

I see that as Shrinkage...and I was not in the pool.

I think the "Hay Day" for airframe size, was way back in the mid 1970's-1980's, when oil was cheap, and the 747 ruled the international routes, at Pan Am, TWA, United, NW, American, even Delta had a few. Those companies also had L10-11's, DC 10's, etc. Oh, and on the domestic side of the house, they started buying 767's, 757's and still had a lot of 727's. Those were replaced by the MD 88 and 737-800's at Delta.

Where are all those 747's, DC10's, L10-11's today? And where are the 767's and 757's going? Same Place, the Bone Yard.

I don't see that as airframes are getting bigger over time.