How would we bet? (I wasn't the downvote you refer to though)

By 'airforce action on the dam' I assume you mean aircraft bombing of the dam. By when would this happen? (ie when would the bet be closed?)

[edit] I will admit I thought your idea was crazy, but you are not totally wrong looking into it, but this is about Egypt objecting it being filled in one year, which they'll let pass if conditions are ok rather than war, and going from talking about it to actually bombing it means they have think about what if Ethiopia bombs the Aswan Dam in response. Geneva Convention also comes into it.

They won't do it, all over it's being filled to quick. Bomb some military installations to make them slow down instead.