I use my wired xbox controller for flying jets/helos and have the same issue. My controller mapped perfectly for Arma 2 and Arma but in Arma 3 I can map all of my flight controls except the shoot button to the trigger not sure why. One idea is that after you map it, it shows right trigger as being read as an X-axis button not a trigger? Might be the game is reading the button wrong. As far as infantry and ground vehicles I prefer the good ol keyboard/mouse combo.

Agreed does seem too fast