Also note that there will not necessarily be let's say "five Boeings, four Airbuses and two BAe's" on every market refresh. The selection of aircraft types it puts up there is purely random and it is only looking at the total number of aircraft for sale, it must be at least XX (where XX is comparable to number of players in the game world, and also partly of how long the game has progressed).
The ones being sold at the market for long enough without being leased are taken off. First their price is reduced, and after that they are retracted from sale. If the sale fails 3-4 times, the broker will scrap the plane (= hopeless to sell/lease). Most of the russkies have not yet rotated thru this process I believe so that's why there's so many of them, and naturally of course because the "good ones" are leased out very quickly.
(I do acknowledge that the present is not the best situation ... there's a thread in feature rq forum about this, pls pop ideas to that thread)