Join Date: Dec 2002
Location: Danville, CA, USA;
Programs: UA 1MM, WN CP, Marriott LT Plat, Hilton Gold, IC Plat
Posts: 18,106
I barely missed the last flight of the day @ ORD and was offered standby on the next available flight (the following morning). Alas I needed to return the same night so I switched to UA and lost the value of the VX ticket.
One would presume you would be booked into the same class that you purchased, but of course that may be sold out on the next flight.