Add onion and ground beef to a glass dish that will fit in your Air Fryer. Put in the Air Fryer.
Cook for 5 minutes and then carefully pull out the rack and use a spatula to break up the ground beef. Add garlic, Worcestershire, and mustard. Stir until combined, and cook for another 5 minutes or until the meat is no longer pink. Remove and set aside.
Add two pieces of toast to the Air Fryer and toast for 3 minutes - flip halfway through.
Pile meat onto the roll or bread, top with pickles, and cover. Repeat until you have four sandwiches.