Delta Air Lines will offer lie-flat business-class seating on domestic flights on six more routes next year as customer service on US domestic long-haul flights continues to become more competitive.

Atlanta-based Delta already offers lie-flat seats on the New York JFK-Los Angeles, JFK-San Francisco, Boston-San Francisco and Washington National-Los Angeles routes.

Starting April 1, 2018, Delta will offer lie-flat seating in both directions on two of three daily Boston-Los Angeles flights, two of four daily JFK-Seattle flights and one of three daily JFK-San Diego flights. Also from April 1, it will offer lie-flat seats on daily Atlanta-Honolulu and Minneapolis-Honolulu flights (it flies once daily on each route).

From May 1, 2018, Delta will offer lie-flat seats on one of five daily JFK-Las Vegas flights.

Over the summer, Chicago-based United Airlines began offering lie-flat seats on Boeing 777-200 flights between Hawaii and five domestic hubs: Chicago O’Hare, Denver, Houston Intercontinental, New York Newark and Washington Dulles. United also offers lie-flat seats on Boston-San Francisco flights, Newark-San Francisco flights and Newark-Los Angeles service.

Dallas/Fort Worth-based American Airlines and Delta this year brought back no-fee meals for all economy passengers on select transcontinental flights.

New York-based JetBlue Airways has said Airbus A321s equipped with its lie-flat Mint product now make up the majority of its transcontinental capacity.

Aaron Karp