Fly Swatter - Assassin's Creed: The Ezio Collection - ACII

Kick a guard using the Flying Machine - 5

This is done in DNA Sequence 8, Memory 5 - you use Leonardo da Vinci's Flying Machine to fly, kicking off Templar Guards off in the process.

You need to fly close to a Guard and kick him off the roof, pressing Left Trigger.

If you are playing the The Ezio Collection Edition, after DNA Sequence 12, there will be another Flying Machine in the North of Forli. You can also kick guards off roofs, or kick them while they are on the ground.

Sketch of Leonardo da Vinci's Flying Machine