Thank you for your interest in the US Army. A recruiter would be able to fill you in on all the particulars, but....
Airborne is parachuting out of an airplane. Further information can be found at
And Air Assault Involves repelling out of helicopters.
As far as the benefits of each school? That depends upon who you ask.
Both Airborne and Air Assault are highly sought after schools that are often more difficult to get into than by just "volunteering".
To get INTO either school, you'll need be on assignment that requires one, OR stand out amongst your peers and "earn" a slot given to units, OR swing some kind of deal from recruiting or retention-- although that last option may not always be available.
As stated before- Airborne is parachuting out of an airplane. Air Assault does involve repelling out of helicopters, however, it is equally distributed between learning about rotary aircraft, sling-load operations, and then repelling.