Spawn aircraft at same altitude on different maps

hey guys

im making a custom kill streak now this can only work at a certain altitude of a spawned plane. now there 2 ways you can help me

1)give me the code that will make it no matter what map im in the hight of a spwaned aircraft will be the same

2) (the one i don't preffer) tell me a code to find if the map = Afghan or high rise or any other map so that it will work out so like this

if Afghanistan

plane = spawn (0, 0, 1000);

if highrise

plane = spawn (0, 0, 5000);

thank you very much

Peace

if(getDvar("mapname") == "mp_namehere"){
//stuff
}