You can use the IATA (International Air Transport Association) website to check your passport, visa and health travel document requirements: iatatravelcentre.com/passport-visa-health-tr…
If you contact the airlines directly they will not give you an answer and basically tell you the passenger is responsible for having the proper travel documents and that you should check with the countries you will be transiting/travelling to and/or possibly the IATA.
You can read the airlines Contract of Carriage that explain their rules with respect to passports. For example, from Westjet's Contract of Carriage Rule 5 Passports and Visas:
5.1 RESPONSIBILITY OF PASSENGER
(a) Each passenger desiring transportation across any international or transborder boundary shall be responsible for obtaining all necessary travel documents and for complying with the laws of each country from, through or to which he desires
transportation, and unless applicable laws provide otherwise, shall indemnify the carrier for any loss, damage, or expense suffered or incurred by the carrier by reason of such passenger’s failure to do so. The carrier shall not be liable for any aid or information given by any agent or employee of the carrier to any passenger in connection with obtaining such documents or complying with such laws, whether given orally or in writing or otherwise; or for the consequences to any passenger resulting from his failure to obtain such documents or to comply with such laws.
We arrived in PV on Saturday Feb 9 and returned on Feb 15 (had to return home early for family reasons). Our passports renew on May 18,2013 and no one said anything about them.
Canada, Mexico and the US are all part of the '6 month club',