Everyone's got a rule for booking cheap flights, and most of it gets repeated without anyone really explaining why it's supposed to work. Airline pricing is run by software that adjusts fares as seats sell, not by some fixed calendar rule, so a lot of the advice you hear holds up fine, and some of it just doesn't.
What's actually true
- Prices do climb as a flight fills up. That's real demand pricing at work, not some sneaky trick
- Flying midweek tends to be cheaper because business travel demand drops off, and that pattern is pretty consistent
- Booking early for peak routes like school holidays or big events genuinely does protect you from the worst price jumps
What's mostly myth
- Clearing your cookies or browsing in private mode to get a better price. Airlines don't price based on your browser session
- There being one "magic day" to book on. The pattern is softer than that and varies by airline, it's not some universal Tuesday rule
- Prices always bottoming out at exactly six weeks before departure. It really depends on the route and the airline
What actually moves the needle
Being flexible on dates matters a lot more than timing your search perfectly. Shifting a trip by two or three days, or flying out of a nearby airport instead, usually saves more than any clever booking trick. Setting a price alert and just buying once it drops to something you're happy with beats trying to guess the exact bottom.