The Cheapest Day of the Week to Fly

What the data shows

Wednesday departures are the cheapest on the largest share of routes, at 25 percent, with Tuesday next. Thursday is the most expensive day, averaging 6 percent above the cheapest day on the same route. The pattern matches what airline pricing implies: business demand fills the start and end of the working week, leisure demand fills Friday and Sunday, and the leftover days keep their cheapest fare buckets open longest.

Method: for each route we record the lowest one-way fare seen for each departure date in cached search data, covering the current and next month. We average those daily lows by weekday, divide by the route's mean so that expensive and cheap routes count equally, then average the indexes across routes. Routes with fewer than fourteen dated fares, or with a weekday missing, are excluded. Fares are recorded lows rather than live quotes.