Chalupas and tostadas are almost identical, especially as they're both usually made from using very similar ingredients. However, the main difference between the two is their shape. While both of them are fried, they both hold their shape very differently. The tostada is flat, which makes it easier to eat. Whereas the chalupa is curved. Chalupa literally translates to "boat" in Spanish - so if you're wanting to load up on fillings, the chalupa is the way to go (even if it does get a bit messy!).