Taxi Transportation to/from the airport
At the airport there is an office to book an approved taxi . The office is called Cooperativa de Transporte Expreso Tocumen R.L. You will find the offfice as you leave the Immigration Department; they are open 24 hours. You can book a taxi for $30.00 for up to 3 people, and $10.00 extra for each additional person.
You can see their webpage at http://setvipanama.com/nosotros.html. However, they don't have an online booking of taxis. You can reserve at +507 220-1210 or 220-1832 or 220-8127