Pegula, whose billionaire parents own Buffalo's NFL and NHL franchises, won the singles title in Austin defeating compatriot McCartney Kessler 7-5 6-2, but hung around as Kessler and Zhang Shuai lost to Yuan Yue and Anna Blinkova in the doubles final.
With the players then facing a quick turnaround ahead of the Indian Wells main draw beginning on Wednesday, Pegula offered to fly all of them to California for the WTA 1000 tournament.
Zhang thanked Pegula for her generosity on Instagram, adding they would otherwise have faced a late-night layover in Los Angeles or trips to nearby airports in Dallas and Houston.
"You know she can leave away right after her singles final, but she is such a selfless and generous girl," Zhang wrote.
"This message is NOT to show I took the jet, just wanted to appreciate and transferring the love."
Blinkova also shared Zhang's story on Instagram and thanked world No.4 Pegula, who has amassed more than $17 million ($A27m) in prizemoney in her career.
China's Yue also expressed gratitude to US Open runner-up Pegula on social media for the luxurious ride.
"Otherwise, we would all have been on the road for at least nine hours," she added.
