Aircraft market

How often are aircrafts released into the aircraft market? When someone decides to lease out their own aircrafts or when some company goes bankrupt?

Private lessors can place aircraft on the market at any time.

AS Lease places aircraft on the market either after somebody bankrupts, or after somebody releases aircraft from leasing and returns it back.

there's no fokkers? :(

Well depending on the server, there probably aren’t any Fokkers, as they are a very popular aircraft.

There are Fokkers on Kaitak.  I'm running them at this point, all of them (F27,F28, F50, F70 and F100)  :P  but only 70 and 100 bring good profits