My gentle friends, I do not mean to bust up the party, but in today's world, $30,000 is really not a whole lot of money. As you move along in life and your chosen career (whatever it may be), you will have the opportunity to earn quite a bit more. However, I am not discounting what all 30K can do for anyone right this minute.
If you really want a career in aviation, you have no other debt and no dependents, then sure, invest the money in flight school. You never know about your choices until after you made the choice anyway. SkyHigh will have a different opinion, I'm sure.
Or you can invest it in law school and like me, fly because it's fun.