Old Dec 24, 14, 8:09 am
  #4  
channa
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Join Date: Aug 2002
Location: Bay Area, CA
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Originally Posted by mherdeg View Post
But the big downside is that if the inventory is out of date (either for UA flights, someone else buys it; or for non-UA flights, the connection with another carrier is poor and they get bad availability data), you'll see this error page. UA will think they can sell you the seat, but once you hit "pay" you will have a bad time as they try to grab the space and their reservations system says "can't grab, it's not available".
Great explanation. One more nuance to go into -- the website uses ITA to provide search results, but UA's back end is SHARES. So if ITA has the inventory, and the inventory is legitimately there, but it's not available in SHARES (quite common, actually), it will barf.

Another nuance is how SHARES is slow to update flights. I booked a ticket with UA involving an AC flight. The AC flight had moved by about 20 minutes a few days prior to my booking. It showed correctly at united.com (ITA), but wouldn't confirm because SHARES still had the flight at its old time.
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