DALLAS — Southwest Airlines executives on Thursday unveiled their vision for Southwest 2.0, an airline that for the first time will give passengers assigned seats, charge them extra for more legroom and offer red-eye flights but bags still will fly free. The airline announced that it plans to end the open-boarding system it has used for more than 50 years and start flights with assigned seats during the first half of 2026 as it responds to shifting consumer tastes and tries to reverse a three-year slump in profits. CEO Robert Jordan and other Southwest executives outlined the future refresh during an investor meeting in Dallas where they tried to convince shareholders that they can increase revenue by winning over younger and more affluent customers. The moves away from Southwest’s simple business model and quirky traditions come as airline management faces pressure from activist investor Elliott Investment Management.