Demand -- where are the numbers?

OK so I am starting my first enterprise in airlinesim. I have already researched several aircraft families, and in spite of some previous recommendations here to go for Boeing jets, the aircraft plannig tools shows me better break-even points at various price points and ages, for A320-light, and in second option A320-medium.

But my question is I cannot seem to find a place where I can see the DEMAND for a particular route, e.g. BOG - JFK, for example. I cannot order a 180-seater jet if maybe the demand for routes will fill only a smaller A319 instead. So where do I get the demand numbers for a specific route from?

There's no way to know if there is a demand. It's all about trying and learning. But a good tip would be, look into the airport you wish to operate in, in the real world. What routes are running now etc. And try to start with short haul routes. They can serve your long haul later on in the game.

demand on the game is dependent on demand in real life, so follow what Banff said.

also look at building a strong network and offering good connections to important destinations. This will be key to giving you a good SLF and good margins initially.