Both quiche and frittata are baked breakfast or brunch dishes made with eggs, cream, and a variety of cheeses and fillings.  The main difference between the two is that a quiche is typically baked in a flakey pastry crust, while a frittata is generally crustless.   Because quiche has a sturdy outer crust, they also contain a larger percentage of cream and milk compared to eggs so they have a more custardy filling.  Meanwhile, frittata are much eggier and almost closer to the consistency of an omelet.