EASA, the short version.
Not long after the initial start of powered, controlled flight, the American authorities decided that a body should be put in place to regulate and promote aviation, this body being entitled the Civil Aeronautics Administration. This blossomed into the now worldwide Federal Aviation Administration. The FAA have done an excellent job of making practical and generally well thought out regulations for all aspects of aviation, from ATC, through manufacturing, maintenance and operation of aircraft.
The disparate European countries all had their own regulations as did the UK, in our case, administered by the Civil Aviation Authority. The French had the DGAC, the Germans the LBA etc, etc. and they were all different.
The large transport aircraft market became filled by American manufacturers. Boeing, Douglas, Lockheed, etc following the demise of the UK aircraft manufacturers (and to a similar extent, the French).
Then a new kid appeared on the block, Airbus. This conglomerate was made up of European manufacturers, each constructing sub-assemblies of the embryonic Airbus A3XX series of airliners. A far more affordable route for the European manufacturers.
But the various European countries were looking much further ahead. They wanted to be able to shoulder up to the great FAA on an equal footing. This would mean that all the European aviation authorities would have to amalgamate into one body. In the early 1990's, the Joint Aviation Authorities was the result, and aviation was introduced to Joint Aviation Requirements. Think of one new set of GUIDELINES for all European countries. Guidelines, because none of it was ratified and made law. The UK CAA, always wanting to be at the forefront, enforced almost all of these new guidelines as mandatory. The basic idea of one set of rules throughout Europe sounds almost sensible. However, each and every Member State retained the right to change or ignore any part or whole of any of these guidelines. It was a shambles.
Airbus, gained parity with the American manufacturers a couple of years ago in terms of hulls constructed per annum. Well done.
Unfortunately, over a decade ago, it was accepted by the EU that JAR's weren't working as originally envisaged. So they changed the name to European Aviation Safety Agency (EASA) rewrote and ratified the regulations, and they rushed it. Unfortunately, it is now law, and it is taking over ten years to try and sort some of it out. Another shambles. Industry was not consulted in any genuine sense. Graduates sat around tables and made regulations about subjects that they had absolutely no experience of. And the rest of us have had to pick up the pieces and huge bills. It has not been, and is still not a good experience.
The reality is, industry was very happy with the idea of one system. Any of us on here knows that the "one system everywhere" worked in the UK Armed Forces. There was never any doubt, as the general rules were the same, no matter where you were posted. The aviation industry was almost unanimous in the idea of adopting the largest civil system in use at the time, the FAA system. Politics wouldn't allow it.
To give some idea of the EASA regulation creating process, a working group was drafting up another new regulation, this one for the requirements for the carriage of radio and other Nav aids in an aircraft. After considerable quantities of ink and coffee, complete with rounds of back slapping, the UK representative enquires about the regulations for aircraft that were non-radio. None of the European rule-makers were aware that an aircraft could possibly be capable of flight without a radio.
Camlobe
You couldn't make it up.