APIs to airline reservation systems already exist, they're just supported by the likes of Amadeus that provide the relevant IT infrastructure to the airlines as

APIs to airline reservation systems already exist, they're just supported by the likes of Amadeus that provide the relevant IT infrastructure to the airlines as well as distribution services for travel agents and OTAs to book [nearly] all the airlines Since finding and booking flights is actually trivially easy for the consumer already, it's actually in the interests of airlines (as well as the middlemen) to be cautious about who gets access to which API function, especially when it comes to actually selling tickets. At the extreme end of the scale, some low cost carriers can only be booked on their website, because they make more in upsell from the booking flow than they could make with extra bookings from other channels