How can I get from Guangzhou to the Hong Kong Airport for an 11,15am flight?

Well, you can take a coach to HKIA from Dongshan Hotel, Yuexiu South Coach Terminal, Hai Tao Hotel, Hotel Landmark Canton, Garden Hotel, or China Hotel, etc. The first coach is scheduled at 5:15, and the trip takes about 3.5 hours. Set off early in the morning, and you can catch the flight. Good luck!

you go Guangzhou South rail station and take as early as the 6:33 am Bullet train to Shenzhen North station, gets you there 7:06 am , take short taxi to the futian border crossing , cross bridge into hong kong , take another taxi (35-45 min ) to hong kong airport

check this timetable , if you want to take later train