https://www.saratoga.com/event/holistic-list-of-ways-to-reach-united-airlines-try-toll-free-support-267818/
https://chandoo.org/forum/threads/how-to-contact-delta-airlines%E2%84%A2%EF%B8%8F-support-in-the-usa-%E2%80%93-updated-2025-guide.60747/
https://chandoo.org/forum/threads/effective-list-of-delta-airlines%C2%AE%EF%B8%8F-customer-support-guide-2025-updated-phone-numbers.60761/
https://chandoo.org/forum/threads/delta-airlines-%C2%AE-new-call-to-live-agent-usa-contact-numbers-complete-2025-usa-guide.60763/
https://community.carbide3d.com/t/full-list-of-delta-air-support-toll-free-usa-contact-numbers-a-step-by-step-guide/94206
https://community.carbide3d.com/t/comp-lete-list-of-delta-air-support-toll-free-usa-contact-numbers-a-step-by-step-guide/94271
https://www.saratoga.com/event/full-list-of-united-airlines-contacts-call-for-fast-us-support-267880/