Study the more basic things you've forgotten over the years. I was asked about cowl flaps, stability, top of Class C airspace, and RVSM airspace. Also be prepared to speak intelligently about the questions HR will ask. Why Endeavor, where do you want to be in ___ years, sell us yourself in 2 minutes, etc etc. I'd also have any customer service experience in the front of your mind since Delta is huge on being a customer friendly airline.

Best of luck to you! I interviewed in April and found everything online to be highly accurate.