Credit/Debit card surcharges (or discounts for cash are really interesting) - it's fascinating that the only transparent charge for merchants - the merchant discount rate - is such a big target...

Any form of payment has a cost associated with it even "free" payment forms such as cash or check. With Cash - in addition to physical security, reconciliation, possibility of loss, bad notes etc. etc. - there's also (many times) bank charges for depositing cash beyond certain amounts. In addition, there's several studies that show that Cash customers average amount of purchase is significantly smaller (one can argue they only spend what they can afford which is better etc. - but from a shop keepers' standpoint don't I want them spending more?)... Check, of course, has associated costs as well - reconciliation, bad debt (NSF/bounced check) and bank charges too....

Obviously any person paying with any other form of payment is "subsidizing" the cost of the other payments. I would argue that if you pay with a debit card you are probably paying the "highest" subsidy for all other forms of payments. In general, debit cards are probably the "lowest" cost especially after Durbin, for a merchant. So - thanks - I'll keep enjoying my rewards while cursing out those people inflating my Starbucks latte by $0.01 because of their insistence on paying cash or check. (not to say I don't enjoy standing behind you while you count out $4.21 in pennies, or fumble with your checkbook to find the prettiest design and write out a check slowly, in cursive).

Enjoy your flights