Thanks to Doug to bring up the question.
US registry database is updated fully automatic on a weekly basis. The updates include current and de-registered aircraft. So in most cases it's not necessary to manually add a US tail number. Though it did happen that an aircraft disappeared from both de-registered and current database.
Canadian registry database is updated manually and irregularly by myself. Fully automated update is in my to-do list. The same rule on manually inserting US tail number applies to Canadian ones.
UK registry is a bit different. I can't download full UK registry database from internet, however I can check one aircraft at a time. I have found a relatively complete UK database somewhere on the internet before, and imported it into our database. If a visitor is search for a UK tail number that does NOT exist in our database, the program will automatically check with CAA (UK civil aviation) website for that number. If information is found, a new record will be added into our database. We can call it semi-automatic, because it's initiated by our visitors.
We use same method on Swiss (HB-) registry as UK.
Above information only applies to civil aviation. Military registry are fully manual and are contributed by our visitor for most part of it.
stantonite was right, we don't encourage visitors to add US, CA, UK or swiss aircraft manually, because there's a chance to disturb the consistency of our database. For example, if you search for a UK civil aircraft, and was presented with "Add new aircraft" page, that means we can't find it in our database, and can't find it in current UK registry, so there's a big chance that the aircraft registry number was typed wrong. If the visitor continues to add it without double check, a fake record may be created in our system.
Again, all above only applies on civil aviation.
Ken
