A generic drug is actually its brand-name equivalent, although it doesnt bear the original trademark and looks slightly different.
Note that although Regular Airmail is trackable in most cases as well, tracking information becomes available only on delivery (or attempted delivery) of the order.
Courier delivery is much faster and provides a benefit of being able to track your parcel in real time via the USPS website.
According to the recent FDA data, generic drugs account for about 45-50 percent of all prescription drug purchases in the United States.