Transit: Mexico City - Beijing - Kuala Lumpur - Beijing - Mexico City

Both of those are allowed under the Transit With out Visa. There is no restriction against separate airlines and separate tickets so just bring print out of the Hainan and Air Asia confirmations.

Paul is correct EXCEPT you will need the KL and Mex City tickets, not just printouts of the confirmations.

OK, Confirmation page should have ticket number present. Most of the time this will be viable, in case of ticketing delay make sure the confirmation email shows the 16 digit ticket number.

Richard, currently all airline tickets are electronic which means that anything with the ticket # on it will suffice. Said # would only be found on a confirmation or a boarding pass, so Paul is not wrong there.

Thank you Paul, Richard and John, I've checked and Air Asia allows you to get your boarding pass up to 14 days in advance, so if this would be enough then we would be covered. We'll be reaching the US office of Hainan tomorrow just to make sure we won't have any issues.

I've flown with Hainan a few times, should be no problem to locate a something you can print showing the ticket number. If you booked through Hainan you can also use the confirmation number to pull up the e-ticketing confirmation if you don't have it in your email. If you used travel agency website for example Orbitz the confirmation. I know when i used Expedia Hong kong took 24 hours after booking before the ticket number was attached to the confirmation. Similar steps can be taken with Air Asia.