All these features were cut however, the sound files of underwater & drowning still exists in common/client folders in BF2. The player would dive for 30 seconds underwater before drowning and there were rumors about underwater and toxic gas/poison weapons. With the v1.3 patch, the game (and specifically this expansion) is solid.

During very early stages, there was supposed to be diving underwater & even underwater levels, as seen in this video. : Battlefield 2: Special Forces Expansion Pack - PC : Video Games.

This is the only of the Battlefield 2 Expansion packs to not feature any Jets, however Jets were originally supposed to appear in Special Forces as seen in the player's commo rose and there is also audio relating to jets for each faction.

Navigating perilous streets and alleys, the SAS must push towards the palace, but the Insurgents have the area well-guarded and won't give it up easily.' The SAS have been called in to execute a surgical strike on the Warlord's compound and surrounding Insurgent strongholds.

His reign of terror is about to be challenged. 'An Insurgent Warlord has been commissioning attacks against British forces in the area with tremendous success, using local civilians as a shield against retribution.

Battlefield 2 special forces patch