Do you need visa to change airport in US from JFK to LaGuardia?

For a flight from Ireland to Canada (Ottawa), with a visa for Canada, do I require a US visa to get outside the airport for this airport transfer? My itinerary has a stop over New York and I have to change airport from JFK to LaGuardia.

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia…).