Please allow at least 4 hours between terminals, to account for flight delays, check-in, bus and train delays, etc. The combined rides take no more than 1 hour overall:

Take the Q33 bus that stops outside all LaGuardia airport terminals, follow signs to buses. The Q33 will take you to 74th Street/Broadway, a major transportation hub, called Roosevelt Ave-Jackson Heights. You will be let off inside a mini-bus terminal, go downstairs after paying fare at the turnstile and down any staircase ON THE SAME SIDE AS THE GLASS WINDOWNS, NOT OPPOSITE IT. This is called the Jamaica-bound side, take the E train to Supthin-Blvd/JFK Airport station (caution, in the early morning and late afternoon weekdays, a few E trains go to 179th Street instead, listen for announcements and if so, get off at the next stop and wait for the next E towards Jamaica Center.)

Once at Supthin, go upstairs for the JFK Airtrain, follow signs through the Long Island Railroad terminal, it is in the back.

Fares:

If you are able to get a single fare Metrocard at LaGuardia, it’s $2 for the bus ride, with a free transfer allowed to the subway at Roosevelt Ave. If you can’t get the card, pay $2 in coins, no dollar bills accepted on the bus. Once at Roosevelt, get a $7 card at the booth just inside the bus terminal, $2 for the subway and $5 needed for the Airtrain ride from Jamaica to JFK Airport.

helicopter – the Grand Central / Van Wyck are jokes of roadways -always crowed always under construction and at best never enough lanes.