<prompt> Human: After leaving the country three times in the past 4 months, Ive wondered if Ive been missing out on air miles or by not booking on a credit card with basic spending returns. Any suggestions in regards to a credit card that would be beneficial considering my conditions. Also, would it be worth signing up for various airlines membership programs on overseas flights, even if Im likely to travel through other airlines?Thanks in advance for any advice!Background: My GF and I have been going on international trips at least twice a year, my international travel may actually increase. None of this is work related. Our main airport is Denver DIA. I still use an old Wells Fargo credit card no return. I am not a business owner. We rent, and own our vehicles. We usually travel on a budget via cheap flights, hostels, things like that. I use a Charles Schwab debit card to eliminate any foreign transaction fees.  <response>: Get the card from the airline you use most .My delta Amex has free checked bags a and a free annual companion ticket, but Im sure most airlines will have similar And they will usually be running a promo for new signups 