https://its.comminfo.rutgers.edu/wp-content/uploads/formidable/22/frontier-airlines-customer-service-contact-numbers-in-usa-full-detailed-guide.pdf

https://its.comminfo.rutgers.edu/wp-content/uploads/formidable/22/how-to-connect-with-american-airlines%C2%AE-customer%C2%A9-service%E2%84%97-247-live-person-support-numbers.pdf