Have used Expedia successfully in the past with no problems but will now ONLY use their site to find and compare schedules and fares, not for booking. Never again for booking. I had booked a RT on USAir through Expedia and my return was cancelled by airline due to weather. So far so good - no one's fault, I understand that and I called Expedia to rebook, which they did for the following day on USAir. Here is the warning- Expedia sent me a confirmation ( it says schedule and itinerary " reserved and confirmed" - their exact words). Fast forward 24 hrs later and I get a message from Expedia that the "airline has cancelled my flights". Checked into it with airline and it turns out they have no record of my new booking ( the reserved and confirmed flights according to Expedia). After several hours - literally- on the phone with Expedia, it turns out that the "confirmation "was that Expedia would, when they had time later, request those flights, not that they were ticketed. Please note I am not looking for criticism of me for not understanding how Expedia works - just trying to help others who might be in the same situation. So when Expedia, 24 hrs after their initial confirmation email to me, now finally gets my reservation to the top of the queue in their ticketing department (separate from their reservation department I was told)-- because of the weather delays, by now those flights are long gone and there is no availability for two days. So Expedia ticketing department cancels my reservation. The airline was not even contacted when I made the initial rebooking with Expedia. Lesson learned - never use Expedia for the actual booking- the person that takes and " confirms" your reservation is not getting you an actual ticket. That could happen up to 24 hrs later because ticketing is a different department. In non-peak times this is typically transparent and has no impact, but during peak times or weather delays it makes a huge difference. Bottom line, if I had called the airline directly when I made the initial weather-related rebooking, my ticket would have been issued within the hour. With Expedia they forward your request in a queue to a separate department and you could lose the flight while Expedia takes several hours or ( or over a day in my case) to contact the airline. I called Expedia to discuss my concerns and was very polite to them, but all I got was 3 different people telling me it was not their fault, nothing they could do, they followed standard Expedia process, no error on their end,etc. And repeatedly putting me on long holds. USAir on the other hand was very helpful, got me on a flight (two days later than my original) and told me Expedia should have contacted the airline within one hour of re-booking in order to issue the tickets, esp during peak weather delays. From now on, I see no advantage of using Expedia for booking, I will be using the airline directly.