I book flights for my gf all the time. She has never had to present original form of payment or anything like that. But then again she is a US citizen and the flights have all been domestic. I don't think I have had to present a credit card EXCEPT as a way to try and locate my reservation. Just make sure she has the confirmation number and she should be fine. You could always just call Hawaiian.

Depending on what she prints, she may be axle to see the last four digits of your credit card.