So let's back this up, and make some assumptions about taking out the debt.
At 18 you enter undergraduate and pay $60,000, plus do a flight program so you're in the hole for flight training to the tune of $130,000. Lots of money, right? Maybe.
At 22 you graduate, but you did your training quickly and started instructing at 20. At 22 you're hired by a regional. At 27 you upgrade. At 32 you're hired at a mainline carrier. You make $100,000 a year for 10 years, then $200,000 a year for the remainder. You make $7.6 million over the course of your flying career at a mainline carrier, and have to repay $189.271.20 in student loans back (MAYBE, more on this in a second).
If you make the same assumptions for career expectations, you come out MUCH further ahead, by MILLIONS OF DOLLARS if you're able to get to working quicker.
But what about repayment options? Can you really afford that $1500 a month loan payment every month while you're instructing?
Of course not, and every lender knows this, which is why they have alternative repayment plans.
Let's say you enter into the Pay As You Earn repayment program, because you did your flying in college, and you have Direct Loans through the federal government.
When you're making $15,000 per year you will owe zero dollars per year.
http://studentaid.ed.gov/repay-loans/understand/plans/pay-as-you-earn/calculator