Under the current situation, you should assume that whatever airline you book with will only allow you to take a voucher for future travel, valid for a certain amount of time, rather than a refund if the airline cancels the flight. All airline policies are different on this and expect more changes in the coming weeks. There is no clear answer which airlines are (or will be) more generous or flexible in the future. There is also a massive capacity cut globally, in place for at least a month. What happens after we won't know for a few more weeks. I would thus assume a certain amount of disruption, even into the summer. Ryanair and EasyJet do not operate from New York, they only do short haul flights within Europe.