The Transportation Department has filed a lawsuit against Southwest Airlines for operating chronically delayed flights that caused 180 disruptions. In addition, Frontier Airlines faces a $650,000 fine for similar issues. This enforcement action comes as part of the Biden administration's heightened focus on consumer protections in air travel, aiming to hold airlines accountable for realistic scheduling. Southwest Airlines expressed disappointment over the lawsuit, citing a strong history of operational performance. The DOT has recently also fined JetBlue for chronic delays, indicating increased scrutiny across the industry.