These days tend to have fewer travelers, allowing the Airline to offer discounted prices. It’s a good idea to compare fares over a range of days when planning your trip [+𝟭»»𝟴𝟴𝟴»»𝟲𝟳𝟲»»𝟮𝟭𝟯𝟬)]
https://www.devex.com/people/what-is-the-cheapest-day-to-book-flights-with-delta-2391245
https://www.devex.com/people/what-is-the-cheapest-day-to-book-flights-with-delta-2391245
https://www.devex.com/people/what-is-the-cheapest-day-to-book-flights-with-delta-2391245
