Here’s two excellent source about the Jazz of Gershwin and his influence on Ravel:

An article,

Fascinatin’ rhythm: When Ravel met Gershwin

December 14, 2021 Jack Zimmerman (CSO link)

While in New York, Ravel went to see Gershwin’s new musical Funny Face and declared himself “enchanted.” He expressed interest in meeting Gershwin and hearing him play the Rhapsody in Blue and other jazz-influenced works.

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At a party held in his honor by mezzo-soprano Éva Gauthier, Ravel celebrated his 53rd birthday on March 7, 1928. One of the guests that evening was Gershwin. During the soirée, the young Broadway songwriter entertained Ravel and the other guests with an impromptu performance of Rhapsody in Blue and a selection of songs including “The Man I Love.”

Gauthier later wrote: “The thing that astonished Ravel was the facility with which George scaled the most formidable technical difficulties and his genius for weaving complicated rhythms and his great gift of melody.”

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Ravel spent several nights with Gershwin, listening to jazz at the Savoy Ballroom in Harlem, where dancers did the lindy hop to hot jazz from some of the nation’s greatest bands.

And a podcast:

Impressions in Blue: Ravel & Gershwin

Sticky Notes: The Classical Music Podcast Link

In the mid-1920s, Maurice Ravel wrote a letter to the legendary composition teacher Nadia Boulanger. Boulanger’s class was a mecca for composers, both young and old, and musicians from all over the world vied to study with her. But Ravel’s letter wasn’t on his own behalf. Instead, he urged Boulanger to take on a young student whom Ravel himself had declined to teach. He wrote:

“There is a musician here endowed with the most brilliant, most enchanting, and perhaps the most profound talent: George Gershwin. His worldwide success no longer satisfies him, for he is aiming higher. He knows that he lacks the technical means to achieve his goal. In teaching him those means, one might ruin his talent. Would you have the courage, which I wouldn’t dare have, to undertake this awesome responsibility?”

Boulanger also declined to take Gershwin as a student, fearing, like Ravel, that she might damage his spontaneity and dynamic jazz sensibility. Whether or not the famous story is true (that Ravel turned down Gershwin’s request to study with him by saying, “Why be a second-rate Ravel when you are a first-rate Gershwin?”) we may never know. But the two composers were friendly, and formed something of a mutual admiration society.