There is no AA operated flight from LAX to PPT. UA are starting a flight from SFO but prices appear to be just as outrageous as LAX.
If your trip starts in the UK, it may actually be cheaper to go via AKL. I know one couple that did it LHR-HKG-AKL-PPT and they saved quite a bit over LHR-LAX-PPT or LHR-CDG-LAX-PPT.