A couple of things to know. First, I have had problems from time to time getting the previous trip to clear out of the app. Last week the app essentially stalled on me after I put in my pick up location. Second more applicable to MIA. Uber technically is not allowed at MIA Airport. The very corrupt TLC has had the police bust drivers as they come to the airport. Some Uber drivers are very nervous about the airport and want you to sit up front and not hand them cash, in other words, they want it to appear as though they are a friend giving you a ride to or from the airport.