About 100 planes around the world have been caught up in a scandal that would be cartoonish if it weren’t so terrifying. It saw a dubious company, with fake employees and an address that was a glorified PO box, sell and distribute fake airplane parts that ended up in planes belonging to some of the world’s biggest airlines. On Thursday night, American Airlines became the fourth, and so far final, airline to have found parts from AOG Technics in its aircraft. Southwest kicked off the disclosures from various airlines around the world in early September, when it became the first...