Pricing on Dallas to Cagliari business class swings hard by season. January, February, and March are the cheapest months to fly, followed by a second window in October and November — both sit outside peak Mediterranean travel and outside major US holiday periods, so airlines discount inventory more aggressively and premium cabin award/consolidator space opens up. Summer (June through August) is when Sardinia gets busy with European vacationers, and fares climb accordingly, sometimes pushing past the $6,200 ceiling on published fares even though BestBusinessClass.com can usually still find room in the $4,000s. The general rule: book 3-5 months out for shoulder season travel, and earlier if you're targeting a specific carrier's suite product like Qatar's Qsuite, which sells out on this corridor faster than the others.