Does Egypt have a "tourist season" where tourism seems especially high, and when every place is packed with tourists? If so, when? I'd like to try to avoid that when I visit, if at all possible.

High season is basically October through April. Summer is extremely hot, and tourist numbers drop accordingly.

I'm trying to reconcile that with airline prices.
It seems to me that they would charge less in off season to try to get people to travel more, however the prices for airline tickets have doubled!
I don't quite understand it.

From what I know, many Egyptians go to Alexandria during their summer months to get out of the heat.
Do tourists from outside of Egypt really drop off that much during the hot months? In Cairo that is.

How hot is "hot"? I can generally withstand a lot of heat...I actually like it hot. It's odd that airfares have doubled...maybe something else is behind that.

If I'm not mistaken, and it's possible that I could be, the temperatures in Egypt during the summer get around 120 degrees F. Personally, that's a little too warm for me, but if you like it, I'd say go for it!

Oh my goodness I could not imagine living in heat like that everyday. Is there alot of humidity? Not that it matters at those temps.

Actually it isn't as bad as you may think although I was there one May and it was 53 degess, now that was hot hopefully it wont get that bad in July.