Santana, whose real name is LaRon James, pleaded guilty Thursday to possession of a firearm by a convicted felon and carrying a weapon on an aircraft.
The 36-year-old Totowa, N.J. resident faces up to 20 years in prison when he is sentenced Dec. 12.
Santana was arrested in March.
Authorities have said security staff at New Jersey’s Newark Liberty International Airport found a loaded .38-caliber handgun and unprescribed oxycodone pills in a carry-on bag containing his identification on March 9.
Santana left the area, leaving two bags behind, but turned himself in three days later.
Santana has been free on bail while awaiting trial.