How long before is it cheapest to book flights? - {help }

𝐓𝐡𝐞 𝐜𝐡𝐞𝐚𝐩𝐞𝐬𝐭 𝐭𝐢𝐦𝐞 𝐭𝐨 𝐛𝐨𝐨𝐤 𝐟𝐥𝐢𝐠𝐡𝐭𝐬 +𝟏 -𝟏𝟖𝟔𝟔-𝟖𝟐𝟗-𝟏𝟐𝟗𝟕 (𝐔𝐒𝐀 ) 𝐨𝐫 +𝟏 𝟒𝟒-𝟐𝟎𝟑𝟗-𝟕𝟒𝟓𝟏𝟕𝟑 (𝐔𝐊 ) 𝐭𝐲𝐩𝐢𝐜𝐚𝐥𝐥𝐲 𝐝𝐞𝐩𝐞𝐧𝐝𝐬 𝐨𝐧 𝐭𝐡𝐞 𝐝𝐞𝐬𝐭𝐢𝐧𝐚𝐭𝐢𝐨𝐧, 𝐬𝐞𝐚𝐬𝐨𝐧, 𝐚𝐧𝐝 𝐚𝐢𝐫𝐥𝐢𝐧𝐞.