In answer to the question in the thread title, "Can you book a flight without a credit card?" I know in the past the answer was definitely yes. Way back when travel agents were common and airlines had city ticket offices, paying with a check or even cash was possible (I've done both). Travel agents do still exist, but I can't say if they still accept cash or checks. I suspect the ones at the AAA Service Center nearby would take checks if you're buying far enough in advance, but I can't guarantee it. I know AAA takes my checks for care repairs.