As far as I remember you can get a ticket that gives you a ride up to Ngong Ping and then to Tai O. From Ngong Ping to Tai O is like 30 minutes by bus. From Tai O you should be able to get back to the airport within 1 hour. It should be possible to do both if you are fast, and that you don't have to wait long for the bus.

I like Tai O quite some because I'm not a fan of Buddha. It's beautiful and you can see the old fishing village (a bit touristy but it's a tourist attraction). You don't have to spend a lot of time there. 1 hour should be enough to walk around and take some pictures. If you are planning to eat there then it takes longer time.