Can I order a uber ahead of time for my early airport ride
The Guru Take
Yes, you can...but some notes.
Yes, you can schedule Uber these days. It's relatively a new functionality, and it's only available in certain cities. See a few threads below.
You should also remember that Uber and other ridesahres are considered as "on-depand service", so they are not so much for built for scheduling rides. The idea is that when you need it, there should naturally be drivers, but there are situations where this may not work.