ok..
How do I join this family
I went sky diving for my 30th., for me yes its an experience that lasts a life time.. get photos and video.
are you sure that everyone in your family will enjoy hang gliding.. there may be be or two that the experience will simply be terrifying for. You dont have to tell them this is what you are planning, but be round about gauging how they might enjoy being fragile in the elements.
my son eg would not enjoy it so much.. he'd be more like yea yea.. whereas If he went shark diving his adrenalin would rush.. Id loath the very thought of shark diving and probably refuse

)
Im thinking that you are typically very sensible with your money so you have not come to this lightly.. its something you want to do, thats what your money is for..
If your the kind of person that may regret the choice latter dont.
You know .. parents enjoy knowing their children are living life to the fullest as much, if not more than actually doing these things themselves.
If you think that your parents need to hand glide to get the full enjoyment out of it, think again. every new adventure my son ha, I have... so just make sure your spending the money on others to do it for the right reasons.
if it makes fulfilled to do this for them, this is something very special you are giving yourself.
If your not doing this for you then its a waste of money..
Its not $1000 for half an hour. having an experience like this lasts for years.
I recommend that if you do have a garden party planned for afters, sharing the experience is the best part.