Upvote:3
If you're asking about general commercial air travel, no, there is no meaningful, if any, difference in safety relative to time of day.
You can easily argue that daytime is easier on the pilots but considering that aircraft movements are so tightly controlled and the autopilot, radar, TCAS, and other systems are essentially unaware, it's not a huge difference.
However, since there are generally fewer aircraft operating at night, there's less to go wrong.
Busy times can be more dangerous for the ground crew but that's no different that any other industrial setting.
Finally, aircraft don't always start their 'day' in the morning so the many checks happen at all hours. Same for crew.