Airline rules are relatively uniform when it comes to canceled flights. You’re owed either a full refund or a flight of the carrier’s choice — but no fare adjustment.

But what if the replacement flight costs less than the original one? That’s what Michael Sorg wanted to know after JetBlue canceled his flight from Boston to West Palm Beach, Fla., recently.

At the time of the reservation I had the option of booking flight 427 leaving at 5:55 p.m. or flight 429 leaving at 7:33 pm.

After a lot of thought, we decided to book flight 427 even though it cost us about $100 more since it would be a more convenient time for our small children. A couple of months later I received an e-mail notifying me that flight 427 was canceled and I was now booked on flight 429.

I called customer service at that time because I felt that I was entitled to a refund of the $100 that I would have paid if I had booked that flight to begin with. They told me that they could issue a credit associated with my confirmation number.

The more I have thought about this, the more I think I am entitled to a refund back on my credit card. The change in flights was NOT due to my request. This credit forces me or a family member to have to purchase another ticket to use it.

A quick look at JetBlue’s contract of carriage (PDF) will reveal that technically, JetBlue is correct.

Rule 25 states …

Whenever Carrier cancels or otherwise fails to operate any scheduled flight, Carrier will, at the request of the Passenger either (i) transport the Passenger on another of Carrier’s flights on which space is available at no additional charge, or (ii) provide Passenger with a full refund in accordance with Section 26 below. Except as may be provided in Section 37 below, Carrier shall have no other liability or responsibility to any Passenger as a result of a failure to operate any flight.

(Section 37 is its customer “Bill of Rights” and doesn’t address Sorg’s situation specifically.)

So it was no surprise that he received the following reply to an email requesting a refund:

Responding to your letter is extremely difficult for we know the high level of service JetBlue strives to extend to each of our valued customers. We know there are times when we are not able to meet their expectations and still remain within the parameters of our company guidelines.

JetBlue is a nonrefundable airline and we only issue credits. We are very flexible with the credit in that it is transferable so anyone can redeem or even sell. We show you have a credit of $94 which is valid until October 10, 2009 and each of you have a $25 voucher. All vouchers are name specific.

You only need to redeem the vouchers and credit by the expiration date, not travel by these dates.

I read form letters every day, and I think the first part is a little over the top. Do they have some kind of ALT+”extremely difficult” key they push to insert that paragraph? If so, I think they should consider toning it down a little. It sounds too much like a letter of condolence sent to someone’s next of kin.

I suggested an appeal to someone higher up at JetBlue, so Sorg emailed David Barger, the airline’s chief executive. Here’s his reply:

Thank you for your correspondence and taking the time to share your concern. Dave Barger has requested that I respond to you on his behalf.

We appreciate your feedback and can assure you that your comments have been heard. We regret that we are unable to honor your request.

We truly value you as a JetBlue customer and hope you will allow us to serve your travel needs at JetBlue in the future.

I think JetBlue is right — and wrong.

Right, in the sense that it doesn’t owe Sorg anything. If it wants to offer him credit — or nothing at all — it’s well within its rights to do that.

But it’s wrong in the sense that JetBlue failed to appreciate this parent’s perspective. Or to see the big picture, for that matter. A refund might have ensured Sorg would become a lifelong customer.

Now, it’s safe to say he’ll go out of his way not to fly on JetBlue.