This is really easy and you get a lot of xp. Basically all you have to do is join a Drop Zone match and shoot down all of the kill streaks.
Kill Streak XP For Destroying
Care Package Helicopter= 300 xp
UAV/COUNTER UAV= 50 xp
Attack Helicopter= 200 xp
Reaper= 50 xp
All others= 300 xp+

Since it is dropzone there are killstreaks everywhere and if your team sucks alot of carepackages to shoot down. There is usually 4-6 carepackages per dropzone, so every dropzone you can get 1800xp per dropzone plus whatever else is called in.

Class Setup
Primary= any gun with damage at long range so you can shoot down kill streaks when out of Stinger ammo
Secondary= Stinger obv or Javelin
Lethal= anything you can kill yourself with to regain ammo
Tactical= doesn't matter
Perk1= Blind Eye, this is incredibly useful when using this method. Pro is recommended because it takes less time for stinger to lock on to kill streaks and gives your gun extra damage against killstreaks
Perk2= Quickdraw to zoom in faster
Perk3= anything

This method has helped me level up very fast and it is not boosting so there is no chance of getting banned at all.