You cannot fly for the airlines past age 65. Most major airlines will not hire pilots over age 50, although they aren't legally supposed to discriminate. Most airlines prefer not to hire pilots over age 40 unless they have a lot of experience already. The median airline hiring age bracket is 28 to 35. In the USA, the average major airline "new hire" has about 4,000 to 5,000 flight hours and 5 to 10 years professional flying experience already. No airlines in the USA and very few in other countries "sponsor" pilots. Last I knew, the cutoff for sponsored flight training was about 24, but you'd probably have about the same difficulty becoming an airline cadet as getting into the Air Force as a pilot based on the competetion and selection requirements. Outside a jail sentence, a "lifetime contract" isn't enforceable or worth the paper it is printed on.
They can't ask your age.
The oldest you can be and still fly for the airlines is 60. (they may have recently changed this or might change it to 65)