There are a couple of options for getting to Quito's new airport (Mariscal Sucre International Airport) from Terminal Quitumbe (takes around 3 hrs) One way is to take the Metrobus to the old airport and from there catch another bus to the new airport. Second option is to take the Ecovia bus to RÃo Coca and from there catch another bus to the new airport.
If you can avoid the bus, I would because buses take ages to get around and both Metrobus and Ecovia are hugely packed with people so if you have luggage, you can imagine how it will be.
Once you get to the airport, you will find two bus services. The EcovÃa bus transfer departs from RÃo Coca and does less stops. It costs costs $2 and runs from 5am to midnight (departing every 15 minutes). The other bus service is offered by the airport and departs from the "old" airport. This one makes no stops but costs $15-$20.