Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Gander to New York as you normally would.
For a flight from Gander to New York, you will be flying from Gander. Gander (YQX) is just 4.3 km from the centre of the city. Gander is the only Gander airport and it handles 0 outbound flights to New York per day. 0 airlines have flights to New York from Gander on a regular basis.
This is defined as Gander Airport (YQX) and New York John F Kennedy Intl Airport (JFK). Codes like New York John F Kennedy Intl Airport are often used to just call airports uniquely. Ready for more IATA code knowledge? These are related airports for your current travel destination: Newark Airport (EWR), New York LaGuardia Airport (LGA), New Windsor Stewart Airport (SWF), New York Skyports SPB Airport (NYS).