echobeach, the principle as explained by GtE still is valid. Under ICAO rules, all countries will accept you if your aircraft registration and licence (and medical) are issued/administered/validated by the same country, and are at least at the PPL level.
The devil is, in this case, in the exceptions.
The FAA has an exception to this in that they accept a foreign licence to fly an N-reg, but only in the airspace of that foreign country. (So you can fly an N-reg on a UK-issued licence, but only within the UK.)
The UK has an exception that they *implicitly* validate any ICAO PPL for flight on a UK-registered aircraft, and this validation is valid worldwide.
JAR-FCL ensured that all countries that participated in the JAA, have mutual recognition (implicit validation) of each others licences. So you could fly a D-reg on a UK licence since the Germans implicitly validate your UK JAR-FCL licence. And that validation was again valid worldwide so you could fly a D-reg aboad on your UK JAR-FCL licence. (Note that there were some exceptions to this when it comes to medicals.)
EASA enacts EU-wide legislation that basically does the same thing as JAR-FCL: Any EASA licence is valid for flight on aircraft registered in any EU member state. And again that combination of EASA licence and EU registered aircraft is valid for flight worldwide. The main difference between EASA-FCL and JAR-FCL is that JAR-FCL only made proposals that individual countries then had to enact into local law, while EASA can enact EU-wide legislation directly (by going through the EU parliament). (And EASA used the implementation of FCL to shake up JAR-FCL, remove local exceptions, introduce new rules and so forth.)