The name of this sequence is “Necessity, Mother of Invention”. This is story related and cannot be missed. Just complete each of the following memories highlighted by the icon on the map.
- Birds of a Feather
- If at First You Don't Succeed…
- Nothing Ventured, Nothing Gained
- Well Begun is Half Done
- Infrequent Flier
This achievement will unlock at the end of the mission "Infrequent Flyer". The mission contains the only missable achievement in the game, "Fly Swatter", so be very mindful of that.
Before you can actually go and get that achievement, you must first do a test run with the glider beforehand. After running the course, you will then go and make the actual run where you can finally get "Fly Swatter". You will get a quick tutorial beforehand showing you what to do. Just make sure to fly near a guard, and hold to automatically kick him.