United Airlines Chief Executive Officer Oscar Munoz apologized before U.S. lawmakers at a four-hour hearing Tuesday on customer-service issues in the airline industry. Facing questions from the House Transportation Committee about an incident last month in which a 69-year-old passenger was forcibly removed from his seat and dragged down the aisle of an overbooked flight, Munoz apologized for what he described as a “mistake of epic proportions.” “In that moment for our customers and our company we failed, and so as CEO, at the end of the day, that is on me,” Munoz said. The airline reached a settlement with that passenger, David Dao, for an undisclosed sum last week, but the incident has underscored problems in the airline industry that some believe warrant tighter regulations. American Airlines also came under fire last month after an employee nearly came to blows with a passenger in a dramatic scene caught on video. Lawmakers at the hearing threatened to pass legislation to prevent such customer-service catastrophes, but they stopped short of announcing any concrete plans. “If airlines don’t get their act together, we are going to act; it is going to be one size fits all. Seize this opportunity because if you don’t, we’re going to come, and you’re not going to like it,” said Bill Shuster, the transportation committee’s chairman. In addition to Munoz, executives from American Airlines, Southwest Airlines, and Alaska Airlines were in attendance.