why wont my macbook air airplay connect with my ipad? they are all up to date

i have tried to connect my ipad to my macbook air through airplay so i can do the double screen but it isnt working. i click on the airplay icon on the top of the screen but it doesnt show my ipad option. i make sure they are all have bluetooth on and connected to the same wifi but its not working. what should i do to get it to work properly?