But US Airways, like most carriers, doesn't start the clock from the time of your scheduled flight or even from when you had to cancel. It starts it from the time you originally bought your ticket.
In Knauer's case, that meant he now had until March 2013 to use his $443 credit or kiss it goodbye.
As it happened, he didn't have to wait long until he needed to use the ticket. An old friend passed away in Minneapolis in October, and Knauer didn't think twice about flying back for the funeral.
So he went to US Airways' website and tried to book a seat. What do you know? The only seats offered for his $443 ticket were middle seats. But for an extra $29, Knauer was informed, he could lay claim to a window or aisle seat.
Then, of course, there was the $25 fee to check a bag each way. A second bag would have cost Knauer an additional $35 and, God forbid, if he'd wanted to bring a third bag, that would have been an extra $125.
Just to highlight how arbitrary all these fees really are, Knauer said that when he arrived at John Wayne Airport in Orange County to begin his trip, he asked the woman at the US Airways counter if he could change from his middle seat to something a little more comfortable.
"She switched me immediately to an aisle seat and didn't charge an extra fee," he said.
Andrew Christie, a spokesman for US Airways, said the fees-for-this-fees-for-that pricing model helps keep ticket costs down and prevents people from paying for things they might not want.
"Rather than subsidize these services through higher ticket prices for all customers, we have unbundled our services and charge fees to those customers who want them," he said.
"This kind of model has been the norm in the hotel industry for many years, such as charges for mini-fridge items, laundry services, baggage storage and late checkout," Christie said.
Fair points. But an airline's charging for a checked bag or a comfortable seat is closer to a hotel's charging for use of the toilet or shower. Those costs are built into your room rate, just as routine air-travel expenses should be built into base ticket prices.
A trip that originally cost Knauer $443 ended up running more than $600. And that's business as usual for the airline industry.
Oh, and US Airways is now seeking a merger with American Airlines, which would create the world's largest carrier by passenger traffic.
You just know things would only improve after that.