Could this be the year to book your holiday flights extra, extra early? When to book holiday 2026 flightsSo what does that mean for booking holiday travel in 2026? When should you book Thanksgiving flights by? EMILY ELCONIN/GETTY IMAGESWhen should you book holiday flights by? TPG's Summer Hull went ahead and booked her $500-per-person holiday flights, but is using one of those tools (Junova) to monitor the fare in case it eventually comes down.