Correct, if you complete a part 147 approved training program you are authorized to test. Otherwise (you should not need a letter from an airline showing your need for a liscence) just 18 months experience A or P or 30 months combined experience in all ATA's for an A&P. This is subject to review and approval by your local FAA administrator. You need to be fluent in verbal and written English to work in the USA with your liscence (does not read like an issue). A&P school is I believe roughly 1900 hours of training.