An online fare on UAL's website happened to match the fare quoted by a UAL phone agent. When I checked the same UAL website less than 24 hours later, the fare for exactly the same itinerary, dates, times, flight numbers, etc., all exclusively on UAL, had FALLEN by nearly US$40. I'm hearing speculation that fluctuations in the currency exchange rate might be the cause, but I would imagine yield management software would obscure any such variances. Any thoughts, especially NOW, with the cost of crude as high as it is, and the airlines not particularly flush, UAL *particularly*?