I feel sorry for the parents. I hope they are young enough to recoup their losses and still save for their retirement.
Getting yourself in debt to fund an ill timed fantasy is one thing, getting your folks to mortgage their future is another.
You are right to look for alternative methods of funding and if you have any sense of responsibility you will get the old man to pay that 70K back to the bank and cover any losses incurred out your own pocket.
Once you've done that, pick up a broadsheet newspaper, take a long hard look at the economic climate and reevaluate your actual chances of getting a job that enables you to pay this loan back in a reasonable time frame.
At 19 what's the rush to start your trainning at a time when you are likely to finish up when the number of applicants are going to far outweigh the number of airline positions available.