Airports --> User-submitted. Most airports are of high-quality, but as of right now, there are about 3500+ airports published on the servers. The user-submissions ensure proper quality of many airports instead of auto-generated airports, though I think there will be more to come (about 500+ each update).
Aircraft --> I can't say Rotate quality! But high quality, nonetheless. The default aircraft have been truly upgraded and some reworked vigorously. I can promise much better quality and high (very high) functionality for default aircraft, but of course, a group of people working on a list of aircraft AND a simulator is different than a group of people devotingly working on one aircraft. :-)