(Reuters) - American Airlines said on Tuesday it had entered into a provisional agreement to buy 100 hydrogen-electric engines from engine maker ZeroAvia.

The airline said it has increased its investment in ZeroAvia, but did not disclose the value.

Hydrogen-electric engines use hydrogen in fuel cells to generate electricity, which is used to power electric motors to turn the aircraft's propellers.

(Reporting by Abhinav Parmar in Bengaluru; Editing by Vijay Kishore)