These are current links to sites with information about aircraft serial numbers, registrations, and company numbers. I try to keep it current, and weed out sites with questionable accuracy, but I make no claims concerning my success at this.

Joe Baugher's sites
These pages truly set the standard in aeronumerology on the net. Unbeatable for information on US military serial numbers, with nuggets of information on dozens of other air forces scattered through them.
His home page.
US Army and Air Force serials.
Navy and Marine serials.
A very handy search tool for Joe's files.

Australian Military Serials
Another excellent site, combining aeronumerology and general history. Much of my information on Canadian built aircraft in Australia and New Zealand comes from this site.
http://www.adf-serials.com/

UK Serials Resource Centre
Good information on post WW2 RAF serials, starting with WA100. I await their full listing of RAF serials with great anticipation.
http://www.ukserials.com/

Tail number listings
Bits and pieces of information on several different modern air forces (mostly American).
http://www.geocities.com/capecanaveral/lab/6153/tail.html

This data has come from a variety of sources, and may contain all sorts of errors. In the future, I will add a complete list of references. For now, some recent Internet references can be found at the links below.   I would welcome any corrections or additions you may have. Contact me using the link below.