Do you use a comma after hours in the following sentence At 1600 she arrived at airport.?

Yes, you should use a comma after "1600" in the sentence "At 1600 she arrived at the airport."

Here's why:

* Time as an introductory phrase: "At 1600" acts as an introductory phrase that sets the context for the main clause.

* Clarity and flow: The comma helps separate the introductory phrase from the rest of the sentence, making it easier to read and understand.

Corrected sentence:

> At 1600, she arrived at the airport.