https://support.google.com/admanager/thread/307109908/aa-cancellation-policy-for-flight-cancellation

https://support.google.com/admanager/thread/307103149?hl=en&sjid=8668301700467224982-NC

https://community.avast.com/t/what-is-the-cancellation-policy-of-delta-airlines/851364

https://support.google.com/business/thread/307087432?hl=id&sjid=18163820593924342314-NC

https://community.avast.com/t/what-is-the-cheapest-day-to-book-flights-on-american-airlines-faqs/851349

https://www.devex.com/people/american-cancellation-policy-2081579

https://support.google.com/business/thread/307083651/%F0%9D%9F%AD-%F0%9D%9F%B4%F0%9D%9F%B1%F0%9D%9F%B1-%F0%9D%9F%B4%F0%9D%9F%AF%F0%9D%9F%B4-%F0%9D%9F%B0%F0%9D%9F%B3%F0%9D%9F%AD%F0%9D%9F%AF-what-is-the-cheapest-day-to-fly-business-class

https://support.google.com/admanager/thread/307083217?hl=en&sjid=11735037852041909913-NA

https://www.devex.com/people/aa-what-is-the-cheapest-day-to-fly-american-airlines-2081569

https://www.devex.com/people/what-is-the-cheapest-day-to-book-flights-on-american-airlines-2081562