I found it frustrating, but highly amusing that when I tried to use my business credit card (which, it so happens, gives me points towards flights on Southwest Airlines) to pay for a ticket on JetBlue, I kept getting an error message. The transaction wouldn't go through. However, when I paid with a different credit card, the transaction went through right away. Looking at my account's itinerary detail, it showed a lot of canceled itineraries, one for each attempt to pay with the business credit card. Apparently, JetBlue's computer system doesn't approve of my choice of business credit card or its perks.