Sequence 8 - Nothing Ventured, Nothing Gained
Knock to Leonardo door.  Test the flying machine. 
Sequence 8 - Well Begun is Half Done
Machine will require some heat. Our task is to get rid of the guards in four areas, so that Antonio's people could light a fire. The first guard is near us - two others on the edge of the bridge.  Run east for more targets - two soldiers are on the board. 
A third, much larger group of enemies is on the rooftops.  Last two enemies are standing near the water so we can kill them from the river.  When the quest will be done, climb and go to the point marked on the radar).
Sequence 8 - Infrequent Flier
Time to use the flying machine. Left Analog Button ill help you with steering. Press L1 to enemies and hit them. Of course, the most important thing is to fly near fire.  Keep close to the river. 
When you will find yourself outside the channel use campfires located in the villa.  Then get back to the river, towards the burning ship. 
At the end use last campfires  and get into the palace. 
You are on the roof at the moment. Immediately turn right and hide near the chimney.  Climb on the building and jump down on the guard. 
Kill other two archers in a very similar way.  Now go to the end of the roof and go down near the fence. As a matter of fact you will find yourself in the palace. 
Your target will try to run away. Follow him of course and ignore all guards. In the courtyard jump on him and do your job.  Now you have to do something with guards  or just escape through the nearby door.