go here: bf2/mods/bf2/levels/*level name*/server.zip/gamemodes/sp1/16 and open up gameplayobjects.con. i will use karkand for an example:
in the gameplayobjects.con you will find several spawn points
rem [ObjectSpawnerTemplate: CPNAME_SK_SP16_market_HeavyTank] <<<-------spawn point
ObjectTemplate.create ObjectSpawner CPNAME_SK_SP16_market_HeavyTank
ObjectTemplate.activeSafe ObjectSpawner CPNAME_SK_SP16_market_HeavyTank
ObjectTemplate.modifiedByUser dgo
ObjectTemplate.isNotSaveable 1
ObjectTemplate.hasMobilePhysics 0
ObjectTemplate.setObjectTemplate 1 RUTNK_T90 <<<--------vehicle at that spawn point for team 1
ObjectTemplate.setObjectTemplate 2 USTNK_M1A2 <<<----------vehicle at that spawn point for team 2
just change the vehicle code. you could change USTNK_M1A2 with USJEP_HMMVW
now, instead of a tank spawning there, a humvee would spawn there. you can do this on any map, all you have to know is the code for the vehicle, and the name of the spawn points. you dont wanna put a helo at a spawn point under a roof of somesort. that would be bad