You can only pick up the LIRR from midtown and the Jamaica endpoint is the AirTrain which requires a separate fare and another 10-12 minutes to get to the termi

You can only pick up the LIRR from midtown and the Jamaica endpoint is the AirTrain which requires a separate fare and another 10-12 minutes to get to the terminal. Having said that, AirTrain/LIRR is my preferred route into Manhattan on business travel, but I always take an Uber out to the airport unless I've got a late night flight.