This is book 4 of the "Honor Bound" series.

This note contains spoilers for the book.

Published as by W.E.B. Griffin and William E. Butterworth IV. Argentina, and Cletus Frade working for the OSS.

Lots of aviation, including starting an airling and building an airport (actually, both are skimmed over lightly enough to be slightly annoying; though the book isn't short of pages either). Howard Hughes is a character and Cletus gets an American ATR rating in the Lockheed Lodestar and is taught to fly the Constellation.

And nobody, this book, is garotted with piano wire and hung on a butcher's hook. One German couple do defect to the OSS to avoid being sent back to Germany where that would probably happen, though.

I don't find the characters in the Argentina series as engaging as those in the police, marines, or army series, and I don't know or care as much about the surrounding history as the other military series, either.