I don't think it's as complicated as you think.
He knows Teterboro, we know that from the flight logs. He likely has a hangar there for his plane servicing.
He wouldn't fly into JFK or LGA (too complicated commercial airspace).
Other options are too far away drive time to Manhatten.
https://www.paramountbusinessjets.com/cities/teterboro-nj-usa.html
<<pic related
I think its just symantec since Teterboro
is technically part of the New York Metropolitan area.
It is owned by the Port Authority of NY and NJ and would have customs (as the other anon stated)
https://www.panynj.gov/airports/teb-about.html
GodFather 3
The subplot has many thread but ties to a real life banking scandal.
Dug by an anon on the CBTS days...
https://8ch.net/cbts/res/219376.html#219736
Let me summarize
Movie Plot:
Michael Corleone bails out the Vatican Bank
(mafia money) and takes a controlling interest
Real life
Archbishop Paul Marcinkus president of the Vatican Bank
Vatican Bank main shareholder of Banco Ambrosiano
VB embezzles money from -Banco Ambrosiano [chairman (Calvi member of P2 Lodge]
causing it's collapse
There's a spoppy operation called Operation Gladio which involved the Italian, British and the US secret services, CIA, etc, etc as the "post ww2" clandestine operations in the European theatre as a check against Russia.
I'm however, wondering if it goes further back. Recall the "oops" drop of Q team with the Vatican cardinals and Nazi officers?
Maybe even before WW2 because the House of Rothchild became the key bankers in Europe in the 1700's.
The Vatican was deeply involved in affairs of WW2. I use that term loosely because there are many threads there.
If any of you have watched the show Hunting Hitler, the last few episodes of the last season has a number of interesting Vatican connections to the escape to Argentina and how the Vatican provided new ID's and legitimate travel papers to those officers who reach a specific church.