1. how do you, for lack of a better term, slow down the jets as they fly?

I keep getting tailed by opposing jets from behind with no way to break

2. how do you use headset mic communications?

Usually if you pull back on the analog stick it slows you down at a steady pace. Turn off afterburners for sure.
Is your mic on? If so, just talk. Only your team or squad can hear you.

Got it on PC man, mouse and keyboard

Then just press backwards. Same basic principle :P
You ave to pull back so it lessens your speed.

The thing is I tried the backwards thing as you said but it still goes the same speed unless mabye i need to test it again to see

I don't know I will have to check it out i'll bump this thread later to confirm