If you are going to take a taxi in a spanish speaking place and need to tell the driver to take you to the Airport you must say:
'Al Aeropuerto, por favor'
(to the Airport, please)


if you want to be a bit more polite you can also say:
'LLeveme al Aeropuerto por favor'
(Take me to the Airport please)


In case you want to ask the driver the price of the fare it would be handy to say:
'Cuanto me costaria ir al Aeropuerto por favor?'
(how much would it cost to take me to the Airport please?)