Pan Am had one training there and that school in Oklahoma had one too. There were a few training in San Diego somewhere too. I remember that one because that was where they told the instructor they "didnt want to learn how to land, only fly at cruise." The owner of the FBO there said "they were the worst students he'd ever seen." Pan Am in Minn. was where Mosowee (sp?) told the instructors he "wanted to learn to fly Boeings, not Cessnas", which is what led to police investigating him and putting him jail for his immigration status.
Those are the ones I remember, but I know there were more like Huffman in FL and something about American Flyers in FLL too.
The warning signs were out there but their plan of splitting up around the country covered them well and no one except the monday morning quarterbacks figured that one out till all was said and done.