A secured card is a credit card that is backed by a savings account - it is designed to allow you to build a credit history by showing you are responsible to make payments at no risk to the bank (if you default they take the money from the savings account). Your activity is reported to the credit agencies and builds your credit history.

A regular (unsecured) credit card gives you a line of credit based on the banks assessment of your credit history. Your activity is reported to the credit agencies and builds your credit history.

A check/debit card allows you to use the visa/mastercard system to make payments from your checking account. These cards are not reported on your credit history so they do nothing to help build your credit report.

Many banks offer secured credit cards but the Korean Air one is the only airline one I know of and also one of the cheapest & easiest to get. Of course as a US Bank card it is more convenient if you live in a state (mainly the midwest) that they have branches in however as a credit card you can pay the monthly bill by check from anywhere (or open a check account as well and get direct deposit into the account).

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