AA site allows holds. I have never experienced a fare increase, other than when I do not issue within 24hrs and try to re-book. The hold reserves a class of fare, not the fare itself. Most of the travel sites DO NOT RESERVE A SEAT e.g. PreviewTravel, what they call a saved itinerary is NOT a reserved seat or hold. You are not reserving a class of fare! Be very careful when using Internet bookings.