Delta Air Lines has racked up awards in recent years for its on-time performance and improved in-flight service, but recent updates to its frequent-flier program have left Delta loyalists less than pleased. 

We already know about the changes it introduced last year awarding frequent flier points not based on the number of miles you fly, but how much you pay for the ticket. Then it introduced a complicated five-tier award chart that practically requires a code-talker to decipher. Then several travel bloggers noted last week that the airline quietly stopped publishing its frequent flier redemption charts that detailed how many points are needed to redeem various flights. They looked like this: 

Screen-Shot-2014-03-06-at-6 Delta rewards redemption chart. Photo: Via One Mile At A Time

Now, Delta customers are simply redirected to this page with general information, including a note about how "within and between the Continental U.S., Alaska and Canada, round-trip Award Tickets will continue to start at 25,000 miles (plus taxes and fees)." To find out how many points you need to get a flight, you have to actually go through the booking process to get a quote. 

As Gary Leff notes at View from the Wing, this is a problem: "Instead of relying on charts, awards now cost whatever the award calendar says that they do. There’s no pricing ‘promise,’ no price list, and no longer any sense in which a pricing engine is ‘broken’ because the price can’t be compared to a ‘correct’ amount." 

In other words, Delta can charge whatever it wants for reward flights, and those amounts can change at any time. If you're hoarding miles to a book a dream trip, you'll have no idea what goal to work toward. As Brian Kelly puts it, "Making award charts unavailable serves no purpose other than obscuring redemption values to less informed travelers. After all, if you don’t know what the lowest redemption levels are, you won’t complain when they’re not available." 

Now, Delta has delivered another blow: It seems that Skymiles members can no longer book low-level domestic award flights less than three weeks before the trip. While the airline has not explicitly issued any notification about the change, a search for tickets reveals that there are no "saver" level fares (Delta's term for the minimum amount of points needed, now known as level 1) available for flights that are fewer than three weeks out. 

Both American and United charge $75 for award travel that's booked less than 21 days before the trip; until now, Delta did not. But Greg Davis-Kean of FrequentMiler says eliminating last-minute saver fares from the roster is just Delta's way of sneakily charging this booking fee in the form of higher award redemption rates. 

The airline has not said much on the subject, other than to issue the following statement: “There are multiple considerations going into award seat availability resulting in availability that will vary by time and market.”

This is not good news for frequent fliers. And though American and United currently publish their redemption charts, airlines are notorious for adopting such practices after one takes the first step. It may just be a matter of time until we see the ripple effect.