I live in NYC. In November, I am taking a vacation to the Maldives, using United miles. The route I am taking is UA from EWR to Zurich. 4 hour layover in Zurich and then flying Swiss to Delhi. 4 hour layover in Delhi, and then flying Air India to Male, Maldives. Since I am only changing planes in Delhi, and will only be there for a few hours, I don’t see that I need a visa (US Passport only). Can anyone please confirm? I have a US passport.
Short Answer: No, you don't need a visa to change planes in India.
Long Answer: If an airline passenger is refused entry at a transit point or destination, the airline is required to return the passenger to the point of departure at the airline's expense (although they may try to recover the cost from the passenger). Thus, airlines are very careful to determine what documents are required by a particular passenger's travel before allowing that passenger to board. Airlines use the IATA database Timatic to reveal what documents are required.
Putting your information into Timatic through this online portal (there other others), generates this:
India - Transit Visa
Transiting without a visa is possible for:
Passengers transiting through Bangalore (BLR), Chennai (MAA), Delhi (DEL), Kolkata (CCU) or Mumbai (BOM) with a confirmed onward ticket for a flight to a third country within 24 hours. They must stay in the international transit area of the airport and have documents required for the next destination.
Because you're transiting Dehli and have a confirmed onward ticket for a flight to a third country within 24 hours, you may transit India without a visa provided you remain in the international transit area of the airport.