Firstly, let me point out that none of this makes a blind bit of difference to your end position - but it's a fun self-contained problem.
There is one limiting factor at the start of the game: cash. (The number of leases allowed by your credit rating means you can't take out too many bonds, but that's essentially still a limit on the amount of cash available. Make sure you have a positive balance at month-end(?) and on the day you make your bond payments, so your credit rating grows as fast as possible.)
If you want to grow as fast as possible at the start, that means thinking about how to make your cash as productive as possible in the early stages.
Your cash isn't productive while it's waiting for deliveries to start, and that double-build-time for the first plane means ordering 3-week planes ties up your cash for 6 weeks before you see any return. If you order 1-week planes instead, you'll have 3+2+1 weeks of income before the first 3-week plane is even delivered (assuming you allocate them right away).
The other thing to consider early on when choosing which models to order is the produced passenger-capacity per week for each plane. A small plane delivered once a week may give you more passenger-capacity than a larger plane delivered 2- or 3-weekly.