First of the month means new transfers to and from the special fleets. If you are moved out of a fleet you will find a normal fleet invitation when you next login on that character. If you are now eligible to join then please contact us in-game for your invite. It is important to use your best character for the highest fleet you are invited to, e.g. if you get an invite to MACO and Section 47 then put your best character into Section 47 as this fleet has private events and you need to be on the best toon for those very difficult missions.
Section 47 -SRS- eligibility
SRS MACO Spec Ops eligibility
SRS Allied Expeditionary Force eligibility