Want to annoy your online customers? Get them all the way through the order and then tell them they can't have what you pitched them.
Most online retailers play it straight. Seldom do leading online e-retail sites play bait-and-switch with inventory availability or pricing. Information from earlier screens holds true all the way through checkout.
Not so with online ticket search engines. Increasingly, I've found Orbitz, Expedia, Travelicity, and SideStep will "sell" you a ticket, all the way through collecting passenger name and credit card, and then seconds later "discover" that that those attractively-priced tickets are sadly no longer available.
I'm seeing messages like this far too often:
Because flight availability can change rapidly based on traveler demand, the flight you selected is no longer available. Please make another selection. (Message 150)
Yes, airline tickets are dynamic and sell fast, but this issue is happening much more this year than last. The "oops that ticket is suddenly sold out" message is among the most frustrating screens on the web.
There's a growing opportunity for better travel sites than Expedia, Orbitz, and SideStep. I'll try kayak for my next few bookings, but it seems easier these days to buy directly from the airlines. They don't play bait-and-switch games.