For the first time in a long time, it feels like travelers are getting back some of the perks of flying. Airlines are bringing back complimentary snacks, tickets prices aren’t sky-high and some carriers are even doing away with arbitrary fees. But don’t breathe a sigh of relief just yet — now it looks like airlines are getting more creative with how they game us.

Last month, American Airlines (AAL) announced that they were switching over to a revenue-based mileage program. This was a bummer for many customers who realized that they would now have to spend more money on tickets to earn miles and status. It wasn’t initially clear how this change would affect American’s partnerships with other airlines, only that you would be still be able to earn miles based on a percentage of the flight distance and the fare class of your ticket.

Then, when no one was looking, American Airlines updated their awards page with new rates for traveling on partner airlines. Luckily, The Points Guy rang the alarm — pointing out that the new rates have some positive, but certainly more negative effects. Until now, flyers could earn 100% of American Airlines miles with nearly every partner airline in the OneWorld Alliance. Now, the points vary greatly depending on the airline you choose and what class you fly.

For instance, economy ticket passengers used to earn 100% of their American Airlines Aadvantage miles when flying on British Airways. With the new rules, an H class economy ticket is now only worth 50% of the miles. On the other end of the spectrum, business class tickets remain unaffected, and travelers will still earn 150% of the miles flown on British Airways.

Economy class tickets on Alaska Airlines, Fiji Airways, LAN Airlines and Hawaiian Airlines now only earn 50% of the miles flown. It’s important to note here that there are different classes of tickets within each cabin (Y, H, B, L, etc.), so rates can vary within economy tickets.

But it’s not all bad news. In some cases, passengers can now earn a greater percentage of the miles flown. The catch is that most of these cases require you to buy a first or business class ticket.

For example, a first class ticket on a Finnair flight that is operated by American Airlines will now earn you 300% of the miles flown. In addition, a first-class ticket on Alaska Airways is now worth 175% of the miles flown, compared to the previous 150%.

The really bad news is that all of these changes go into effect for travel on or after August 1, 2016. So, if you booked a trip last month on British Airways for a flight this fall, you will earn miles based on the new chart, not the old one. We called American Airlines to ask if there was any way to grandfather in flights that were booked before the change was announced, but they wouldn’t budge.

In other words, if you’re really competitive with earning miles, the only way to avoid missing out on partner miles is to book and take a flight in the next week and a half. Who’s up for a trip to London?

What do you do think about the new American Airlines revenue-based mileage program? Email us at yfmoneymailbag@yahoo.com.