T.F. Green Airport in Providence, Rhode Island
does indeed have a Little Free Library, charter number and all.
It's on the baggage claim level, the ground floor.

If you enter the baggage claim level from outside,
the wooden cabinet will be facing you, facing the outside doors.
It is against one of those wide floor-to-ceiling columns.

The column will be to your right.
It is a column back some ways, near the coffee shop.

I saw it coming down the escalator from the terminal gates,
so of course the column, and the Little Free Library, were to my left.
No paint. Just two-tone wood colors.
And a glassed-over door and everything.