Yes, you get real-time availability when your customers search, but there is a small window where a flight or hotel room can sell out between the moment they see it and the moment they finish booking. This happens because travel inventory changes constantly across the whole industry, and even with live connections to suppliers, there is always a tiny delay between what you show and what is actually still available right now.
When a customer finds something in search results, the system checks availability again at the point they try to complete the booking. If the flight or room has sold out in those few seconds or minutes, the booking will fail and they will get a message telling them it is no longer available. This is rare, but it does happen, especially with popular flights or discounted hotel rates during busy travel seasons.
Your portal can be set up to handle this gracefully by offering customers an alternative search right away if their first choice sells out, rather than just showing an error. The exact way this works depends on which suppliers you are connected to and how their systems communicate with ours, since some suppliers update faster than others.
If you want to reduce the chance of this happening, check with us about the specific travel suppliers and products you plan to sell, since some have faster inventory updates than others.