Here is the full list of all 23 Frequent Flyer achievements.
"Messer" plane unlocked!
Destroy 100 zeppelins
Destroy 100 rockets
Get 5000 score in one game (infinite/organized mode)
"Mustang" plane unlocked!
Get 2500 score in one game (infinite/organized mode)
"Me 262" plane unlocked!
Get 500 score in one game (infinite/organized mode)
Get 1500 score in one game (infinite/organized mode)
"Lock" plane unlocked!
Destroy 50 scout planes
"Pe-8" plane unlocked!
"Spitfire" plane unlocked!
"Il" plane unlocked!
"Sabre" plane unlocked!
Fly 100 games!
Fly 500 games!
Fly 1000 games!
Destroy 50 flying bombs
Destroy 50 minelayers
Get total score of 50000
Get total score of 250000
Get total score of 500000