Track fares for a trip until they hit my target

Track airfare for [origin] to [destination], [dates, or a flexible window like any long weekend in October]. Constraints: [cabin, stops, airlines to avoid or prefer]. My target: [target price] round trip. Each run, check Google Flights for the best current fare matching my constraints and log it — airline, times, stops, price — so you can tell a real drop from normal bouncing around. Stay quiet while fares sit above target; just keep the log. The moment a qualifying fare lands at or below my target — or at least 20% under the recent average — alert me with the exact fare, flight times, how it compares to the trend, whether it looks like a short-lived sale, and the direct booking link. Never book on your own; a fare that good needs my fast confirmation, so make the alert impossible to misread.