Or perhaps more accurately, how many discrete devices will I be allowed to use when at a ticket counter and paying for a single, round trip fare? Domestic? International? How about online with an agent?--here, cash is obviously not involved, though the maximum quantity of "devices" might be.
I seem to be amassing $50 flight vouchers (oh, thousands and thousands.. ) and remember a time when cash, a credit card and ONE voucher represented the maximum combination of devices I was permitted to offer in exchange for airfare.
Hoowzat work now?