The most affordable days to book a flight on JetBlue are generally Tuesday or Wednesday. Airlines, including JetBlue, frequently offer sales and special discounts earlier in the week, which results in lower prices by midweek when demand decreases. Booking in advance, especially during non-peak travel times, can also help secure better deals. However, airfares can vary due to factors such as the route, season, and demand, so it’s always a smart move to track prices and set up alerts to find the best offers.