If you're asking if the air spring can take the place of a lift kit or a lowering kit, the answer is NO. If you're asking if the air spring will cause a normal ride height vehicle to ride higher, the answer is yes if you want it to. By adjusting the air pressure, you can create some lift, but usually only an inch or two.
Assuming you know your way around a suspension and this isn't the first time you've had a wrench in your hand, it will probably take about two hours to install a typical Air Lift kit. If you have access to a hoist and jack stands and air tools, the job can go faster. Always go through the installation manual before you start the job to familiarize yourself with what needs to be done. Installing an Air Lift kit isn't extremely difficult, but it has to be done right to get the best results. Unless you're pretty good with cars, you should let a trained technician install the kit.