i have flown standby plenty. however i have done it w/ delta airlines and they are no longer allowing standby for their passengers at least so they say, i have seen it on a few flights were they are still allowing it but most are not. anyway if you want to catch an earlier or later flight than what you are scheduled for w/in a 3 hrs. time window of your original departure w/ delta, there will be a $25 change fee. if you are changing it and it is more than 3 hrs of your original departure, you will have to pay $100 for the change fee.