There are other ways to save, too, so let's get started. Shop on Tuesday. Best day to shop: The best time to book a U.S. flight is usually Tuesday at about 3 p.m. eastern time. ... Don't Shop too Early or too Late. ... Always Compare Airfare. ... Cheapest Days to Fly. ... Fly the Cheapest Route. ... Book Group Travel One Ticket at a Time. 28 May 2019