Been testing Google Flights alerts for a few months now and LAX–LHR has been my control route. Best deals seem to pop 3–8 weeks out saw a Virgin PE fare drop from $1,289 to $872 just by waiting and catching an early morning alert.
Biggest drawback: doesn’t work well for peak travel. Tried the same for Christmas and just watched fares climb while premium seats vanished. Great tool overall, but for holiday or business travel I’d book earlier rather than risk it.
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