Sign up for our daily newsletterEmail addressSign upI would like to subscribe to The Points Guy newsletters and special email promotions. The Points Guy will not share or sell your email. See privacy policy.This holiday season, one of the best ways to maximize your online shopping is through airline shopping portals. With them, you can earn valuable points and miles with your favorite airline for purchases that you were already planning on making.Yesterday we saw a big boost on United earnings, and now American Airlines is offering a one-day elevation on 15 retailers today, December 6, 2016 until 11:59pm ET, to sweeten up the bonus mileage earning this holiday season. With the following merchants, you’ll earn 15 miles per dollar for today only:NikeNeiman MarcusBoseLivingSocialBarney’s New YorkBackcountrySephoraHarry & DavidSunglass HutShutterflyRosetta StoneWorld MarketJos. A. BankNew BalanceShoebuy.comThis elevated earning could prove to be very beneficial if you’re looking to bulk up your AAdvantage account with miles before the start of the new year. For example, if you make a $430 purchase at Barney’s New York, you’ll get 6,450 AAdvantage miles in return. Based on TPG’s most recent valuations, those miles are worth about $97 — not a bad return for a purchase you were already planning on making!Keep in mind there are some portal-specific rules you should follow to ensure you get all of your bonus AAdvantage miles. For example, make sure you make your purchases directly from the link off the AAdvantage Shopping portal website. If you’re looking to take advantage of these elevations, act quick, as they end tonight at 11:59pm ET.