When you enroll in a pilot training program the licensing path typically follows a progression from basic to advanced levels. On the PilotCET site the licenses are listed as
SPL Student Pilot License (Airplanes/Helicopters) This is the entry level license It allows a trainee to begin flying under the supervision of a certified instructor. It's essentially the foundation license that you need before moving on to more independent flying.
PPL – Private Pilot License (A / H) After obtaining an SPL and building flying experience you can upgrade to a Private Pilot License. The PPL (for either airplanes or helicopters) allows you to fly solo as pilot in command but only for non commercial purposes (i.e. not for hire or reward). PPL training includes both ground theory and flight hours and typically requires a minimum number of solo and cross-country flights.
CPL Commercial Pilot License (A / H) The next step up is the Commercial Pilot License With a CPL (aircraft or helicopter) you are legally allowed to fly for remuneration. This is the core professional license for pilots who want to work in airlines, charter operations cargo or other paid flight roles. Requirements usually include more flight hours. stricter medical fitness (Class-1) and more advanced training.
ATPL – Airline Transport Pilot License (A / H) ATPL is the highest level of pilot licensing. It qualifies a pilot to act as pilot in command (captain) of large transport aircraft in scheduled airline operations. To obtain an ATPL you must accumulate significant total flying experience (in India often 1500 hours for fixed-wing or 1000 hours for helicopters including CPL hours) pass advanced exams, and meet high medical and proficiency standards.
Each stage builds on the previous one: you begin with supervised flight training (SPL) progress to flying solo for pleasure or practice (PPL) then earn the right to fly commercially (CPL) and finally attain the credentials to command airline aircraft (ATPL). The licensing path is structured to ensure that as you gain experience training and skills you're gradually entrusted with more responsibility from hobby flying to serious commercial aviation.