Tips on flying in the USA?

[BackPacker]

Navygm, you need your JAR-FCL PPL validated to fly in US airspace. This is done under FAR Section 61.75 and is informally known as a "piggyback" certificate.

If you search for that number or that word here on PPRuNe you'll find plenty information. And here's the FAA page on this:

Airmen Certification - Verify the Authenticity of a Foreign License, Rating, or Medical Certification