​In the Aviation world, these are the two most important milestones. 

1. CPL (Commercial Pilot License)

​The "Entry Ticket": This is the license you get after finishing flight school.

​Hours Required: Minimum 200 hours of flying.

​Your Role: It allows you to get hired as a First Officer (Co-Pilot). You are officially a professional pilot and can start earning a salary.

​2. ATPL (Airline Transport Pilot License)

​The "Senior Level": This is the highest license a pilot can hold.

​Hours Required: Minimum 1,500 hours of total flying time.

​Your Role: It is mandatory if you want to become a Captain (Commander). You start with a CPL, fly for a few years with an airline to gain experience, and then "upgrade" to your ATPL.

​Quick Comparison:

Feature                               CPL                                                ATPL

Experience                          200 Flying Hours                           1,500 Flying Hours

Primary Job                         First Officer (Co-Pilot)                  Captain (Commander)

Minimum Age                    18 Years                                             21 Years

Knowledge :                         Basic Commercial Ops               Advanced Airline Ops and

Summary: You need a CPL to get the job, but you need an ATPL to become a Commander in an Airline.