Mix flour and salt together.
With a pastry blender, work shortening into the flour and salt until the pieces are about the size of small peas.
In a separate bowl or liquid measuring cup, beat the egg well and mix in the vinegar and water.
Drizzle into the flour mixture a little at a time, stirring to combine with a fork or pastry blender.
Divide dough into three parts and shape into disks.
Cover each disk in plastic wrap. Refrigerate for at least 30 minutes.
For the easy blueberry hand pies, you will only need one of the disks. If you wish, you may freeze the other two disks for use at another time. Roll out one of the disks until it is about 10 inches in diameter.
Mix together all of the filling ingredients in a bowl.
Cut out 6 to 8 4-inch circles from the rolled-out pie crust.
Place about 1 tablespoon of filling into the center of each circle.
Moisten the edges of the circle with a little water. Fold the dough over the filling to form a half-moon shape, and gently crimp the edges with a fork.
Cut two slits in the top of each hand pie.
Spray the hand pies with cooking spray or brush with butter and sprinkle with sugar, if desired.
Preheat the air fryer to 350 degrees, and place 3-4 hand pies in a single layer inside the fryer basket.
Cook for 9-12 minutes, until the crust is golden brown. Let cool for about 10 minutes before serving.