Update: I thought booking flights on Tuesday was the best deal, but my sister proved me wrong
My sister just got back from a trip to Lisbon and told me she saved a bunch by booking her flight on a Sunday night. She said the airline's own app had a flash sale that wasn't showing up on the big search sites (she saved about $75 each way). I always heard Tuesday was the magic day, so I checked for my own trip to Chicago next month, and sure enough, the prices dipped lower over the weekend. I guess the old rule isn't as solid anymore with how often prices change now. Has anyone else noticed a better day to check for flights lately, or is it just totally random?