Black September

The September 11 Attacks, also known as Operation Black September, or just Black September were done not only to avenge the 3,000 Americans killed during the actual 9\11 attacks during the Old Time Line, but also to kill Islamic radicals before they could kill any more American civilians. The attack was coordinated by undercover operatives posing as members of The Marxist Brethren, a right-wing terrorist group, and then hijacking ten airplanes, with the intention of crashing some of them into various Islamic holy sites and al-Qaeda terrorist hideouts (both of which were housing Islamic radicals and their supporters).

Background
Seething with rage over the amount of American casualties in the actual 9\11 event, Slayerz member Lev Ivanovich Raskov sought to avenge the deaths by killing Muslim radicals and their civilian allies. Fellow Slayerz member Olivia Coonz later went along with it. At the same time, The Marxist Brethren and their leader, a reincarnatedKarl Marx, sought to eliminate religion as part of their own war against the Western world and create a Marxist society and had been planning a genocide of Muslim radicals and their allies for years (after Karl Marx grew tired of attacking Christianity). He eagerly accepted The Slayerz's request to assist them in their attack on the Islamic world. For the next five years, The Marxist Brethren help train the Slayerz in time for the operation. As the terrorists had done earlier, the Slayerz are trained to blend into their Middle Eastern environments to avoid arousing any suspicion.

This was the general plan for the hijackers: change their names, pose as tourists, and board the planes. Taking advantage of the less security, they smuggle weapons on board and subdue the crews and passengers at the right time, and then crash the planes into their respective targets.

In addition, Marx instructed that the flights be hijacked in a particular order; once one airplane was hijacked, the hijackers of that flight would text their friends to alert them of the hijacking and that it was "their turn" to hijack their flight. The hijackers of the next flight would then hijack theirs, and alert the buddies on the next flight and so on. Eventually, they were to crash the planes into their respective targets. As for the original flights hijacked during the old time line, they were to simply kill the hijackers and alert the crew on the ground of a hijacking attempt.

The Attacks
The morning of September 11, 2001 was clear and sunny, just as it'd been in the old time line. By 9:00 EDT, the attacks began. Despite air marshalls being present aboard the flights, the hijackers easily subdued the crew and passengers (as well as eliminating the hijackers aboard the original flights from the old time line) and were able to sucessfully hit their targets.