Join Date: Nov 2000
Location: Nashville -Past DL Plat, FO, WN-CP, various hotel programs
Programs: DL-MM, AA, SW w/companion,HiltonDiamond, Hyatt PLat, IHF Plat, Miles and Points Seeker
Posts: 11,405
On domestic, you really do not need anything. If you want to make extra sure, print it out. But, you can do online checkin from home or work before heading to the airport and take the printed boarding pass, which really confirms your ticket.
In International: I would ALWAYS print everything out. $hit happens overseas.