An online travel agency (OTA) is a website that allows travelers to research and book flights, accommodations, tours, and other travel services directly from suppliers. OTAs act as a third-party selling these services on behalf of companies for a commission. The global OTA market is projected to grow significantly, reaching $900 billion by 2032. Common OTA functions include air ticketing, accommodation booking, tour packages, visa services, insurance, and transportation. Popular OTAs include Airbnb, Booking.com, Expedia, and TripAdvisor. OTAs generally operate on a merchant or agency model to facilitate bookings and payments between travelers and suppliers.