Going to Hangzhou from Humen by flight

There is no airport for Humen and the closest airport to Humen is the Shenzhen Baoan International airport.
It is about 25km from Humen. There is Humen Terminal where you can find the direct shuttle bus to Shenzhen airport and the bus journey takes about 30 minutes. The buses to SZ airport are at 06:30, 07:30, 08:20, 09:10, 10:00, 10:50, 11:40, 12:30, 13:20, 14:10, 15:00, 16:00, 16:50, 18:00, 19:00 and 20:00.

Thank you, Thomas. Do you happened to know the estimate cost of the shuttle bus to Shenzhen Airport?

Also, if I preferred Guangzhou Airport, is it too far away to go from Humen to the Guangzhou's airport?

The ticket price is around 30RMB and costs about 40 to 50 minutes.
The Guangzhou airport is far away and from Humen, there is no direct shuttle bus to Guangzhou airport. You need to transfer once before reaching Guangzhou airport. To reach Guangzhou airport, the bus journey takes about three hours.