The Royal Air Force museum at Hendon is one of the world's best, ranking right up there with other greats like the United States Air Force museum. Located in a north London suburb, it's certainly a lot more accessible than the USAF museum, which is tucked away in a backwater in America's Mid-West.
Since this is a museum operated by a government agency, it's not surprising that there are aircraft which simply couldn't be acquired by private collectors, regardless of how much money they have. As well as unobtainable items like modern high performance aircraft, there are also pieces of equipment captured from enemy forces. The prime example of this at Hendon is the collection of German world war two aircraft, with such rarely seen items as a Messerschmitt Me110 night fighter, Junkers Ju 88 bomber and Heinkel He162 Salamander jet fighter.
Hendon is certainly one of the best places to see British military aircraft, from the earliest days through to world war two and then into the cold war. They have a particularly impressive collection of rare British world war two aircraft.