In a medium mixing bowl, combine half the taco seasoning, salt, and ground beef until combined.
In another mixing bowl, toss the butternut squash with the remaining taco seasoning and the olive oil.
Take the shelf out of the air fryer unit. Add the ground beef to one side of the basket, and the butternut squash on the other side.
Air fry at 400°F / 205°C for 8-10 Minutes, opening the basket and breaking up the ground beef occasionally throughout the time. Remove from the air fryer and set aside.
Meanwhile, spread the refried beans on top of each tortilla. Air fry at 350°F / 175°C for 6-7 Minutes, or until the tortilla is crisp and the refried beans are golden brown.
Top each tostada with some of the ground beef, butternut squash, and finish with diced tomato, shredded lettuce, cheese, and sour cream. Finish with a few squeezes of lime. Enjoy!