The information is almost certainly available on the page where you see the search results and choose your flights. Probably right next to or near the flight numbers. It is on every major US carrier's search results. I don't know about any of the OTAs: Expedia, Kayak, etc.
According to the fine print (and carriers' past actions), nothing on an airline ticket is guaranteed as part of the sales contract; not the plane type, flight numbers, arrival/departure times, baggage handling, connections, and, thanks to overbooking, not even the fact that you have a seat on the plane.
