From the Quito airport to the Mitad del Mundo or (Equator monument) there is no easy way to get there by bus because they are located on opposite ends of the city.
We can arrange taxis from the airport to the Mitad del Mundo monument for around $30 one way. Round trip $50. Travel time is about one hour each way. TO get there by bus youll need to catch the city bus into town and then catch the bus to Mitad del mundo from the Rio Coca station (making further connections after that).