Allow about one hour from the JetBlue gate to the Amtrak departure area at Penn Station via AirTrain and the Long Island Rail Road from Jamaica Station. You can purchase your LIRR ticket and AirTrain fare in a single transaction from the LIRR ticket-vending machines at the Jamaica Station AirTrain terminal. (You will need an "off-peak" ticket on the LIRR from Jamaica to Penn Station at that hour.)
Allow about one hour from