Here is the full list of all 35 Eagle Flight achievements.
Eliminate 2 enemies with one Screech Wave
Complete the Notre-Dame chapter
Complete the flight tutorial
Collect all other achievements
Complete the Louvre chapter
Complete the Basilica chapter
Complete the Pantheon chapter
Earn 3 stars on every Ring challenge
Earn 3 stars on every Chase challenge
Earn 3 stars on every Enemy Attack challenge
Earn 3 stars on every challenge
Gather every collectible in the Notre-Dame district
Gather every collectible in the Louvre district
Gather every collectible in the Basilica district
Gather every collectible in the Pantheon district
Gather every collectible in the Eiffel Tower district
Gather every collectible in the game
Be the first eagle to catch the prey in multiplayer
Eliminate 1000 enemies in multiplayer
Deliver 100 prey to your nest in multiplayer.
Win 200 games in multiplayer
Deliver 3 prey back to your nest in one multiplayer match
Eliminate 100 vultures
Eliminate 80 crows
Eliminate 50 bats
Eliminate 50 falcons
Fly for 1,609 km total
Finish an enemy attack with one less Screech Wave than targets
Hit an enemy from over 500 meters away
Complete the Eiffel Tower chapter
Defeat the Grim Falcon
Earn 3 stars on every Feather Rush challenge
Earn 3 stars on every Find the Fish challenge
Earn 3 stars on every Escort challenge
Earn 3 stars on every Tunnel challenge