You can get to Gongbei border from almost every part of Macau within half a hour. Pass the border and find Zhongzhu Dasha (中珠大厦) nearby Gongbei Wanjia Supermarket (万佳百货超市). There are airport bus. TIme: 06:30---21:30, every one hour. It takes one hour or so to Zhuhai Airport. If you can cab from Gongbei to Zhuhai Airport, it may cost 130RMB for the taxi fare. Gongbei border is open at 7am. Prepare half a hour to get through the custom, then 1.5 hours to the airport if going by airport bus. So, you should leave from Macau and get to Gongbei at 7am.