One-One Team

In the Epilogue mission in Call of Duty 4 called Mile High Club, the SAS team that is sent to free a hijacked civilian aircraft are known as the One-One team. If you turn on the subtitles, they do not have names, rather codenames. The leader seemed to be Romeo One-One, you can only hear Echo One-One if you don't free fall off the plane that would soon explode in a little time. He tells you to hurry up. In the epilogue, we can assume that the playable character had a One-One codename.