Many airlines provide inflight oxygen for passengers who require it. However, the availability and cost of inflight oxygen can vary by airline and route, and may require advance notice and medical clearance from the airline.

Here are some major airlines that offer inflight oxygen:

You can find the reference web page and contact information for each airline:

1. American Airlines – Website: www.aa.com/i18n/travel-info/special-assistance/medical-assistance.jsp, Phone: 1-800-433-7300 (within the U.S.)
2. Delta Air Lines – Website: www.delta.com/us/en/traveling-with-us/special-travel-needs/medical-needs, Phone: 1-800-221-1212 (within the U.S.)
3. United Airlines – Website: www.united.com/ual/en/us/fly/travel/special-needs/medical.html, Phone: 1-800-864-8331 (within the U.S.)
4. Southwest Airlines – Website: www.southwest.com/html/customer-service/unique-travel-needs/customers-with-disabilities-pol.html, Phone: 1-800-435-9792 (within the U.S.)
5. British Airways – Website: www.britishairways.com/en-us/information/disability-assistance/medical-conditions-and-pregnancy, Phone: 1-800-AIRWAYS (1-800-247-9297) (within the U.S.)
6. Lufthansa – Website: www.lufthansa.com/us/en/special-assistance, Phone: 1-800-645-3880 (within the U.S.)
7. Air France – Website: www.airfrance.us/US/en/common/guidevoyageur/pratique/special/medicale.htm, Phone: 1-800-237-2747 (within the U.S.)
8. Emirates – Website: www.emirates.com/us/english/help/special-assistance/medical-conditions.aspx, Phone: 1-800-777-3999 (within the U.S.)
9. Qantas – Website: www.qantas.com/us/en/travel-info/special-assistance/medical-conditions.html, Phone: 1-800-227-4500 (within the U.S.)
10. Air Canada – Website: www.aircanada.com/ca/en/aco/home/plan/special-assistance/medical-conditions.html, Phone: 1-888-247-2262 (within the U.S.)
11. Cathay Pacific – Website: www.cathaypacific.com/cx/en_US/travel-information/special-assistance/medical-conditions.html, Phone: 1-800-233-2742 (within the U.S.)
12. Japan Airlines – Website: www.jal.co.jp/en/inter/service/specialneeds/medical.html, Phone: 1-800-525-3663 (within the U.S.)
13. Korean Air – Website: www.koreanair.com/global/en/traveling/special-assistance/medical-assistance.html, Phone: 1-800-438-5000 (within the U.S.)
14. Singapore Airlines – Website: www.singaporeair.com/en_UK/us/travel-info/special-assistance/medical-assistance, Phone: 1-800-742-3333 (within the U.S.)
15. Virgin Atlantic – Website: www.virginatlantic.com/gb/en/travel-information/special-assistance/medical-conditions, Phone: 1-800-862-8621 (within the U.S.)

Please note that these websites and phone numbers are subject to change. It’s recommended to visit the airline’s website or call them directly to verify the information provided.