If you buy tickets on line is that all you need is the reciet is that your ticket?

The ticket I had they just scanned at the gate....I paid for it on line and printed it at home

No.. You will need to have the credit card you used to buy the online ticket. They will run it when you go in the gate.

They scan the ticket's off your phone with the phone brightness all the way up and your good to go

They scanned my phone at ticket office.