Upvote:3
I googled unusual transatlantic flights and got this USA Today article from 2018 so no telling if the all the flights are still...flying.
Most entries had a big airport at one end or the other but this one stood out to me:
Providence, Rhode Island (PVD) to Ponta Delgada, Azores (PDL) on Azores Air. It's summer-seasonal.
Upvote:3
SamanΓ‘ El Catey International Airport (AZS) only has 858 aircraft movements a year, but still has seasonal transatlantic flights to Frankfurt operated by Condor.
San Salvador Airport in the Bahamas (ZSA) has 896 movements a year. It has seasonal flights to Paris-Orly operated by Air CaraΓ―bes. It is on San Salvador Island which has a population of 930.
Picture of the latter seem to indicate a pretty relaxed airport.
For both, that's an average of less than 9 aircraft per week.