Kosher food is available on Copa Airline flights. You can request it on their website within the reservation. It's also available on Avianca flights via a call to their call center.

My experience on Copa has been that they prepare it perfectly or foul it badly. They're supposed to let you inspect and open the package yourself. Also I don't think they know what the oven bag is for. A friendly reminder when they take your order should ensure it's done correctly.