Invaders: No-Prize?

The following letter from Invaders #6 (May 1976) asked artist Frank Robbins and writer Roy Thomas about inconsistencies in the way Sub-Mariner appeared in publications from the 1950s and his appearances in the Invaders (retroactively set in the 1940s).

Dear Frank and Roy:

One question that keeps cropping up in THE INVADERS' letters pages is this: Should the Invaders be part of the regular Marvel Universe? I say that, as of now, they cannot without at least two contradictions. Those two are: Sub-Mariner's wings on his feet, and his ability to fly. He did not get the wings and flying power till SUB-MARINER #38 (February 1955). Do I get a no-prize or anything? I like most anything that is relatively free.

H. Keating DuGarm, Jr.

Then you'd better take to breathing deeply, lad—'cause the petulant Prince Namor did indeed possess those nutty little wings on his feet (which somehow, astoundingly to us all, give him the power to fly for short distances like a flying fish) when he first appeared in the pages of MARVEL COMICS (later MARVEL MYSTERY COMICS) #1, 1939. It was only in the 1950's that, for a few months, he was drawn without them—and that's a period which, despite our reprinting those timeless tales from time to time, we prefer largely to ignore. Or, if you prefer, you may assume that he lost them (along with much of his once superhuman strength) for a few years, only to regain them in the issue of SUB-MARINER you mentioned. You paid your money, H. Keating, so you can take your choice. But a no-prize? It looks as if this isn't the month for readers of THE INVADERS to rake those in, friend!