Momondo and Kayak are not the same, but they are owned by the same parent company, Booking Holdings (formerly The Priceline Group). While they share a similar backend for searching flights, hotels, and car rentals, they maintain distinct brand identities and different user interfaces. Kayak is often seen as the more "corporate" and data-driven tool, focusing on powerful filtering options and price-prediction algorithms popular in North America. Momondo, which was originally a Danish startup, is known for its more colorful, "inspirational" design and is widely considered to be superior for finding niche, low-cost carriers and "hacker fares" in the European and Asian markets. In 2026, you will often find similar results on both sites, but it is still worth checking both because their independent algorithms occasionally prioritize different travel agencies, leading to slight price variations. Essentially, they are "sibling" sites that compete for your attention while ultimately feeding into the same corporate ecosystem.