Originally Posted by
robertablake
I am flying JFK-MAD-LIS (same routing on return). Where will I go through customs/immigrations? Will it be in MAD before continuing onto LIS? Also, on our return, will I go through security again in MAD before boarding our flight to JFK (LIS-MAD-JFK)? Asking the second question in case we pick up any bottles in the Duty Free at LIS.
Immigration in MAD. Customs in LIS.
Edit: you will need to clear security in MAD once you land from JFK before proceeding to Schengen (intra EU) flight departures.
On your return flight, you will go through security in LIS and will be able to proceed to your flight to JFK in MAD without any further security, though you will need to go through exit Immigration.