(Adds details on aircraft financing) Jan 29 (Reuters) - American Airlines has authorized another $1 billion stock sale, following an ongoing $1 billion offering launched in October to boost liquidity, the company said in a regulatory filing on Friday that also detailed its aircraft financing commitments. Only three of 16 Boeing 737 MAX orders scheduled for delivery through next year have committed financing, and American has the right to defer delivery of the remaining 13 until 2023 or 2024, it said. Previous financing for some of the 737 MAX planes that American was meant to receive in 2020 had expired as Boeing Co froze deliveries during a 20-month safety ban that finally ended in the United States in November. American said financing was in place for the 19 Boeing 787 aircraft and 15 Airbus NEOs to be delivered this year, but not for any of the 26 NEO aircraft deliveries scheduled for 2022. Bankers say aircraft financing is broadly available for mainline aircraft that provide solid dollar-denominated returns, but any tightening of availability could affect deliveries. Wrestling with a historic slump in air travel due to the coronavirus pandemic, many airlines have deferred or even canceled airplane orders and rushed to raise liquidity to ride out the crisis. American’s new stock offering follows a stock surge on Thursday after the carrier was mentioned on Reddit’s WallStreetBets forum. On Friday the stock was 2.3% lower at $17.68. From the October equity offering, it has raised $882 million so far at an average share price of $12.87. Separately, American said it did not expect a material impact from the cancellation of some 300 flights operated by its wholly owned regional subsidiary PSA on Thursday following maintenance issues. Most of the aircraft have been returned to service or will be shortly, it said.