Recently I traveled with American Airlines. I had a bad experience as I felt they were terribly outdated, so I complained with their customer service, who, ironically, gave me a paper voucher that I can redeem on my next flight.
Now... seems like this paper voucher that looks like a plane ticket can't be used while booking online, is that true? How I can redeem it? I read somewhere that I have to do a phone reservation and then mail the voucher. Really? That's so outdated