Get the starting plane md83 and sell asap for max cash.
Get dhc6s on short routes, then some turboprops. 10 of former and say 20 of latter will quickly build amd sustain building a pile of cash for "proper jets". I binned the dhc6s after a few years as they ate slots on routes that justified larger but kept turbos for ever!
Some go for the cheap russian aircraft, I used 757/767 to get established as intended to keep for game.
Spam ifs and near zero wage are only real way of keeping up with others or all routes "taken", and in this one competing cant really start for a long old time. Some tried the trick of low freq massive price but that looke vulnerable to competition (one of few times you can successfully compete!).
Ordering in bulk to get big capital savings (and quick shared maint costs) is more important than ever, but then again you have to trade that with the waiting time whilst others may get on routes. I went for aircraft as soon as could afford it, but the big winners went for bulk.
Good one though, i really enjoyed it but then i wasnt trying to win and everything i wanted to do worked out.