How do volcanoes affect air travel?
Volcanic ash can clog and damage airplane engines and has lead to crashes and near-crashes in the past. If a volcano is erupting and producing ash flights may be redirected or cancelled. In 2010 the eruption of the volcano Eyjafjallajokull in Iceland cause air travel in Europe to essentially shut down.
The time of day has practically no affect on volcanoes. The movements of underlying rock layers and geologic structures determine volcanic events. The weather (wind, rain), which is affected by daytime heating, may affect the result of an eruption, in that ash plumes may be either transported farther or washed from the air more quickly.