As a rule, evening and night flights can be booked cheaper than morning and day flights. But you should consider, for example, the need to pay for a cab or an extra night at the hotel. Low-cost carriers have the most expensive tickets on Sunday (+15-20% off the average price), and the cheapest airline tickets are on Tuesday and Wednesday (-15-20% off the average price). A departure on Friday and Saturday will cost you 5-10% more than the average price.