The 99th Aggressors (Tactical Air Group), was formed on December 9, 1999 at 9:00pm EST.  
During the years 1998-1999, online combat flight simulators were just emerging on the internet. Simguild's Flying Circus was an active WW1 simulation at that time. A simple, yet very enjoyable World War 1 simulator, with an amazing flight model.
As with most online combat sims, you end up joining a virtual squadron, to enhance game play and to learn from others.
The founding members of the 99th all originated from an existing online squadron, called the "Skylords". A very well established squadron, that completed against the best of the best. Arabian Knights, Jasta 18's, Skelton Crew, just to name a few.
In the fall of 1999, a problem arose within our squadron. The Commanding Officer, who had been absent for the past several months, returned and became active (daily) in Flying Circus. The problem started when he would constantly be telling everyone what to do, and how to do it. It had gotten to the point where, the fun went away. People were not happy. Something had to be done.
So a few decided to call a meeting, but not before resigning from the Skylords.
On the 8th December 1999...seventeen members of the Skylords submitted our resignations. We then set a meeting date for the very next day...December 9th at 9pm EST. 
We held our meeting on ICQ (chat program at that time) and in this meeting we came up with our new squadron name and appointed positions of responsibility.
Positions of responsibility. The 99th is a unique group, as it is our belief that every member of our squad is as important as the next. Therefore our Officer positions within the Squadron are positions of responsibility and not ones of authority.  This ensured that we will never have to endure someone telling us how to have fun, and we also felt that it extends respect to our members. We are ALL the same. We are ALL 99th.
Since that day, our squadron has been active in several simulations, and not just air combat. We dabbled in Nascar Racing, Call of Duty and Battlefield from EA Sports. Today, our only "active" simulation is the WWII  simulator, Aces High
We are 20 years old this year. Our group has remained in place, and most of us still keep in contact. Few of us....still actively flying

First 20 years...we rules the skies. Cannot see that changing anytime soon, eh Rose?  

Long live....the 99th ASTAG