Better english structure;
Do you have UAV, Airstrike and Harrier
Killstreaks; UAV, Precision Airstrike, Harriers
Get Harrier (The UAV and Airstrike throw it, only Harrier)
Get enough kills for Harriers (The UAV and Precision you can use, you only need to keep the Harrier)
Dead and now get Airstrike (The UAV throw it, now you should have Airstrike and Harrier)
Now die and this time get enough for Precision (You can use the UAV, You should now have a Precison and then a Harrier)
Dead and again get Airstrike (Again throw the UAV, no keep it)
Die again and get enough kills for another Precision (Again, you can use the UAV)
Now with Airstrike, Airstrike and Harrier, in that order, quickly throw the two Airstrike and quickly the Harrier.
Now with 2 Precisions and a Harrier backed up, quickly use all three.
When after all the air Harriers have two rather than one that just threw.
After all the strikes have finished, you should find 2 Harriers stay instead of just the 1 you called.