Well I've currently got a fleet of 25 A320s ordered around 1993, my server is currently in early 1996. I think I'll probably replace around a quarter or so of my A320s with 737-800s when they're available and wait a couple years, probably like 2 or 3 and replace a few more A320s with brand new ones unless I find I make way more with the 737-800.
It's an American based airline, so I think it's of great importance when to buy American when possible. But for the 90s I really don't see how the 737 Classics could beat the A320s.
I also have A319s and A321s on order I figure I will supplement future A319 orders with 737-700 orders I get to wait a little longer on the A321s lol since the 737-900 and ER versions aren't out for awhile lol
Wished my game didnt end in 2015, because I'd love to get the C-Series now the A220 in service but I don't think that'll be exactly a great idea lol