'Air tacos' are exactly that: corn tortillas folded and fried with no filling at all.
The empty fried tortillas are topped with lettuce, cream, cheese, pico de gallo or pickled pork skin and salsa, and are sold at the same stands that sell guacamayas.
Why it's made this way: They are a favourite botana of León, where locals eat them as a snack at gatherings and while watching football.