Yes! The only thing you’ll need to check into your flight online is the confirmation code you got when you booked it, which doesn’t usually appear on your e-ticket. And if you’re checking in at the airport, the ticket agent will use your ID to find your ticket information in their computer system.
Once you’re checked in, you’ll get a boarding pass; you need a boarding pass (either on paper or electronically on your phone) to board the plane.