https://official-delta.odoo.com/knowledge/article/36 https://official-delta-airlines.odoo.com/knowledge/article/34 https://official-united-airlines.odoo.com/knowledge/article/34 https://official-united-airlines-helpcenter.odoo.com/blog/our-blog-1/ways-to-contact-united-customer-service-by-phone-and-email-a-step-by-step-guide-1 https://official-united-airlines-helpcenter.odoo.com/knowledge/article/38 https://official-delta-airlines.odoo.com/blog/our-blog-1/ways-to-connect-delta-airlines-customer-service-by-phone-and-email-a-detailed-guide-2 https://official-delta-helpcenter11.odoo.com/knowledge/article/34 https://official-united-airlines.odoo.com/blog/our-blog-1/ways-to-contact-united-airlines-customer-service-by-phone-and-email-and-other-methods-a-detailed-guide-1