飛機起飛時間20︰15pm 如想由上水到達機場，應該幾點到？

最遲6點45分要到機場

if no triffic jam it is like an hour to go to airport fr Sheung Shui, two hours in advance, so I suggest you leave home at around 5.15pm, by the time u get to airport would be around 6.15pm, half hour check in or other stuff, then go and see and shop around airport, that would be prefect! if u dont want to shop, leave at least an hour in advance. but u dont wanna everything to be in hurry right?