MIAMI — While American Airlines posted record third-quarter revenue of $13.7 billion, the workers preparing food and beverages for its flights say they’re struggling to make ends meet. And they’re not staying quiet about it anymore. Dozens of airline catering workers employed by LSG Sky Chefs rallied Friday at Miami International Airport, calling attention to what they’re describing as unlivable wages and inhumane working conditions. These are the people responsible for assembling those in-flight meals and drink carts you see rolling down the aisle; they serve American, Delta, and United, among other carriers. And according to the workers represented by UNITE HERE Local 355, the contrast between airline profits and their own paychecks has become impossible to…..