Booking flights at the optimal time can often result in significant savings. While there's no one-size-fits-all answer due to fluctuating airfare trends, cheap flights understanding general booking patterns and tips can help you secure cheaper flights:

1. Early Booking for Popular Routes: For popular routes and peak travel times (like holidays and major events), it's generally advisable to book flights in advance. Airlines often release their cheapest seats early, and as demand increases closer to the travel date, prices tend to rise.

2. Domestic Flights: For domestic flights within your country, aim to book tickets around 3 weeks to 3 months before your departure date. This window typically offers a good balance between availability and price.

3. International Flights: International flight prices can fluctuate more widely. It's recommended to book international flights 2 to 6 months in advance for the best chances of securing lower fares. However, some airlines may release discounted seats closer to departure if they haven't filled all their available seats.

4. Avoid Booking Too Early: While booking well in advance can be beneficial, booking too early (more than 6 months ahead) may not always guarantee the lowest prices. Airlines often adjust their pricing closer to departure based on demand and seat availability.

5. Last-Minute Deals: Contrary to popular belief, last-minute deals are not as common as they used to be. Airlines now tend to increase prices for last-minute bookings, especially during peak travel times when demand is high.

6. Tuesday Afternoons: While not a hard rule, some studies suggest that airlines may release discounted fares on Tuesday afternoons. This timing coincides with the traditional "airfare sale" days of the past, although discounts can occur at any time depending on airline strategies.

7. Off-Peak Seasons: Traveling during off-peak seasons (like shoulder seasons between major holidays) can often result in lower airfares. Airlines may offer promotions and discounts to stimulate demand during quieter periods.

8. Flexible Dates: If your travel dates are flexible, use tools like fare calendars on flight search engines to identify the cheapest days to fly. Flying mid-week (Tuesday, Wednesday, or Thursday) is often cheaper than weekends.

9. Monitor Price Trends: Use fare tracking tools and set up price alerts to monitor fluctuations in flight prices. This allows you to capitalize on price drops and book when fares are at their lowest.

10. Consider Connecting Flights: Sometimes, booking a flight with a layover or connecting flight can be cheaper than a direct flight. Explore different routing options to find the most economical choice.

Understanding these factors and staying proactive in your search can help you find the best time to book flights at the lowest prices.