Here is the full list of all 5 RealFlight Evolution achievements.
Complete the "Apprentice Experienced Mode I" Flight Training course
Complete the "Habu Experienced Mode I" Flight Training course
Complete the "AeroScout Experienced Mode I" Flight Training course
Keep your aircraft aloft for 2 hours (7200 seconds) of total flight time
Keep your aircraft aloft for 4 hours (14400 seconds) of total flight time