Senior lawmakers urged US airlines on Tuesday to fix their customer service issues after recent high-profile problems, or face a crackdown from Congress.
"Seize this opportunity because if you don't, we're going to come and you're not going to like it," said Republican Representative Bill Shuster, chairman of the House transportation committee.
The hearing was Capitol Hill's first chance to grill airline executives since the violent removal of a passenger from a United Airlines flight last month sparked global outrage.
The executives were grilled on the growing consumer anger directed at airlines, which came to a head when Dr. David Dao was dragged from a United flight at a Chicago airport on April 9 to make room for crew members on the aircraft.
It is the chance to learn "what is being done to improve service for the flying public," Shuster said in a statement.
Munoz apologised again and reviewed changes the airline has implemented in the wake of the incident, including reducing the amount of customer overbooking and offering passengers up to $10,000 in compensation to be bumped off overbooked flights.
"We will do better," Munoz promised.
American Airlines said it also would reduce overbooking and planned to reach out to customers before they arrive at the airport if flights are oversold.
Joining Munoz at the hearing was United President Scott Kirby as well as executives from American Airlines, Southwest Airlines, Alaska Airlines and a consumers' union consultant.
Southwest Airlines announced last week it would stop overbooking entirely, and Alaska Airlines said it is working to reduce overbooking.
The airline executives also pledged to simplify their disclosures to customers when tickets are purchased. Lawmakers criticised documents of nearly 50 pages long as confusing and inscrutable to the lay person.
"All of the language in the contracts favour the airlines," said William McGee, an aviation consultant with the Consumers Union.
Lawmakers griped about crammed flights, confusing pricing policies for food and bags and excessive fees for customers who change flights.
Some lawmakers also complained about lack of competition following a series of mega mergers that has restricted choice in many regions around the United States.
"Across the board, we all know it's a terrible experience," said Representative Michael Caputo, a Massachusetts Democratic .
But several lawmakers in the Republican-led Congress signaled they were loath to step in with new regulations.
New actions from Congress risks a "one size fits all" approach bad for consumers, Shuster said.
But he warned, "This issue is not going away. We're not going away. We will hold you accountable."
TRT World spoke to Douglas Kidd, Executive Director of the passenger rights group Right to Fly about the significance of the congressional hearing.