5:00am Taxi from Orta San Giulio to MXP

Is this at the conclusion of the RS Village Italy tour?

If you're on the Village Italy tour, talk to your guide. She will arrange taxis to MXP.

Keep in mind that an 8.30 am flight is not a direct flight back to the US so 1.5 to 2 hours is enough for check in and security at that time of morning.

If you are not on a tour, and staying in a hotel, you can ask them when you check in. They should know which companies are available at that time.

I would ask the hotel to book a taxi for the time you want. You cannot rely on finding a taxi on the street at 5 am on a Sunday in a small town like that.

If you’re on the Village Italy tour, your guide will help with arranging a taxi. Ours started asking a few days into tour because of the shortage of taxi’s in the small town. If not, check with your hotel because they will most probably be able to help you but don’t wait til you get there, do it now. We just did this. We left at 7 am for a 10 am flight to our Zurich connection and It took an hour to get from Orta to Malpensa but it was a Monday morning and lots of traffic. Otherwise, we were told it’s normally 45 minutes but ‘dependo.’. Also, leaving before 8 am is extra fare for some reason. They prefer cash and charge extra if you want to use a credit card. Small town Italy with few options, whatever, we made our flight without stress :-)

Keep in mind that an 8.30 am flight is not a direct flight back to the US so 1.5 to 2 hours is enough for check in and security at that time of morning. (Frank)

What if the "8:30AM" flight is the BA flight to LHR? You sure the 1.5 to 2 hrs is 'enough'?

Perhaps OP did a bit of 'rounding' on the departure time and is on the 8:40 AM Delta flight to New York?

In either instance one must go through the Schengen exit processing. I suspect most would suggest being to the airport earlier than "1.5 to 2 hrs" ahead of flight time.

OP did not disclose the destination of the flight and thus 'assuming' it goes to a Schengen destination is perilous.