would destroy vs would have destroyed

[MichaelLu2000]

Should I use “would have destroyed” and “had approached” instead of “would destroy” and “approached” in the parts in bold?

"At the end of WW1, countries didn’t use airships for large-scale airstrikes anymore. Improved anti-aircraft cannons would easily destroy any slow, large airships if they approached a major city.”

 

[teechar]

First, please cite the source of that sentence. It is a legal requirement.

 

[MichaelLu2000]

First, please cite the source of that sentence. It is a legal requirement.

It’s a sentence I made up so there’s no source. I’m just wondering which one I should use.

 

[5jj]

"At the end of WW1, countries didn’t use airships for large-scale airstrikes anymore. Improved anti-aircraft cannons would easily destroy slow, large airships if they approached any major city.”

A hypothetical situation at the end of the war.

"At the end of WW1, countries didn’t use airships for large-scale airstrikes anymore. Improved anti-aircraft cannons would easily have destroyed slow, large airships if they had approached any major city.”

A counterfactual situation towards the end of the war.

 

[emsr2d2]

It’s a sentence I made up so there’s no source. (You are the source!)
I’m just wondering which one I should use.

To avoid unnecessary delays with threads, please always make it clear in post #1 if you wrote the text yourself. Otherwise, we'll always assume it's from somewhere else and request the source information. Thanks.