Deus Ex/LaGuardia Airfield

Battery Park
As you start the level on Battery Park, go to the subway entrance. If you rescued the bum at Hell's Kitchen's basketball court:
 * Enter the western shack, where two bums are talking. After their conversation, talk to the male bum, Curly, and he'll give you the phone booth code.  Proceed downstairs.

If not:
 * Go downstairs and pay Harley Filben for the phone booth code (6653).

Step up to the phone booth on the western side of the station. Enter the code and stay inside the booth until it stops moving. Continue through the underground tunnel, and climb up the ladder.