13% is the number that explains why OTAs need hotels to keep working

Thirteen percent. That is the share of airlines' online passenger revenue that flows through online travel agencies (OTAs), according to Phocuswright estimates in the latest report U.S. Online Travel Agency Market Essentials 2026.

It is easy to miss inside a report that opens with steadier numbers: U.S. OTA gross bookings rose 4% in 2025 to $100.3 billion, OTAs now represent one fifth of all U.S. travel gross bookings—and that share is projected to reach 21% by 2028. Read at that level, the OTA model looks intact.

The segment breakdown tells a different story for air specifically. Air's share of OTA gross bookings has declined to 20%, driven by travelers migrating to airline websites and apps and by airlines using tighter capacity and higher fares to reduce the incentive to shop elsewhere. Only 13% of what airlines earn online passes through an OTA at all. Airlines have kept the online air customer largely for themselves.

Hotels are the segment doing the work the industry narrative credits to OTAs broadly. Hotel bookings represent 63% of OTA gross bookings, and even there, growth has slowed as overall U.S. hotel room revenue growth cools. The 4% headline growth rate and the rising 21% share are, in large part, a hotel story wearing an OTA-wide label. Air is not a growth lever for OTAs anymore. It is a segment airlines have mostly closed off. 

That concentration is the risk the top-line numbers hide. A hotel slowdown would not be offset by air, because air has already been ceded. It would need to be offset by the segments still growing inside the OTA book, packaged trips, cruises, activities and other supplier categories filed under "other" sales, all smaller and less proven at scale than hotels. The industry's overall growth rate looks stable. What is actually stable is one segment, and this report's own numbers show that segment's growth cooling too.

The 13% figure is one data point inside Phocuswright's U.S. Online Travel Agency Market Essentials 2026, which covers market sizing through 2029, segment-by-segment shares for air, hotel and other categories, and the competitive dynamics shaping Expedia, Booking and the OTAs built around them. The full report also digs into where artificial intelligence, B2B expansion and packaging investment are having the most impact on growth.