Wait, so… does -copter come *from* helicopter? 

Yep! This is called rebracketing. Another famous example would be “-burger”: the original food item is named after the German city, [Hamburg]+[er], but got semantically reinterpreted as [ham]+[burger]. Now it’s used as a suffix indicating a type of sandwich.

#language is made up and nothing is real (via @gallusrostromegalus)