Most airlines have partnerships with booking sites, provide an API, pay the booking site a commission, and have a pricing structure that lets them profitably se

Most airlines have partnerships with booking sites, provide an API, pay the booking site a commission, and have a pricing structure that lets them profitably sell tickets at the advertised prices. Ryanair doesn't pay a commission to booking sites, and their pricing model is to advertise $15 flights but making booking an obstacle course so plenty of passengers find themselves paying $60 instead. They therefore don't provide an API for the booking sites to use.