Which airline was the first to introduce lie-flat seats in business class?

British Airways was the first airline to introduce lie-flat seats in business class.

British Airways introduced fully flat beds in its Club World business-class cabin in 1999. The design allowed passengers to sleep horizontally rather than reclining in a conventional angled seat, marking a major change in premium-cabin comfort.

The airline arranged the seats in a distinctive forward-facing and rear-facing configuration known as yin-yang seating. This layout allowed more passengers to receive a flat bed while preserving efficient use of cabin space. Privacy screens helped separate neighboring passengers.

Lie-flat seating is often confused with angled-flat seating. An angled-flat seat reclines substantially but does not create a level sleeping surface. British Airways' 1999 product is specifically associated with the first fully flat business-class bed, while other airlines later introduced competing suites, doors and direct aisle access.