OK, but remember that just because you
can have high frequencies and/or lots of planes on the same route, it isn't necessarily a good idea.
Plenty of threads where you can read more about this, so I'll try to sum it very briefly: the higher the number os seats you offer on a route (either through multiple frequencies or with more than one plane), the lower the fare you can charge and still fill the plane. Most times it's far better to add a different route than to overdo a single one.
For instance, you may soon learn that at 0.5x frequency, you make more than half the money you'd be making at 1x frequency. So, if you can have that plane doing two routes with 0.5x instead of just one at 1x, you'll probably have higher profits. This, by the way, is the origin of the "no more than n.5 flights on each route."
As for leasing vs buying. Expensive planes may not be profitable to lease, but small and cheap planes normally are. Very much so, indeed. Since you've just started, you probably have very little money. If you wait until you have enough to buy another plane it may take days. Leasing a cheap plane is a great way to start growing with a very little investment. Sure, you'll pay the lease every month. But since you'll be taking in profits every day, as as long as the profits are enough to pay the lease, you'll get richer, faster.
