Try AA LAX-JFK-POP. If you take the red-eye from LAX to JFK, you can take the 6:30 am JFK-POP and be in your hotel room in POP before lunchtime. Other alternatives would be a similar routing on CO via EWR, on AA via MIA or SJU, or taking Pan Am or Aeromar from the EWR or JFK, respectively.
Brian