If you're an invited guest, most hotels will send a car to the airport for you and take you back when you leave.

There are commercial shuttles that make most of the Strip hotel stops; get one at the airport with no reservation required. Cheaper than a cab but takes longer as your hotel may not be first.

I understand that you can call private cars (like Uber) for airport tranportation now but I've never used them.

South Coast does have their own shuttle to/from the airport since the commercial transportation doesn't go that far South. Good idea to make a reservation with the hotel.