If you are at a Disney resort, there are certain airlines that have check in at the resort (I think American is one, but may be wrong). If you are offsite or on an airline that does not have that service at a Disney resort (like Southwest), then you will either have to find a computer to use at the hotel/resort etc., or wait to check in after you get to the airport. Most airlines now have kiosks where you can enter your name, confirmation number or credit card and check in right there and print your boarding pass without having to get in the normal check in line. I believe American does. An e-ticket just means you will not receive hard copies of your tickets in the mail like the days of old when you actually received a ticket booklet.