Violin case can be found in the manager office rh side.
in the garbage bin is a bomb and on the wall the cam. can be found if you are in 
the bank window. Gun on the rh side of the saboteur

Give botox to the adv. Lady to get some free ad.
Give the violin to the saboteur to be able to perform sabotage.
Give the gun and the bomb to the saboteur to unlock extra sabotage
Give the security cam to the protection dude for eyes and ears. To unlock extra safety.
Handheld mirror goes to the security guy for some special services.

You enter the room open the inventory select the item click the hand button and then 
You speek to the person, this unlocks some special offers.
There are more things but not been able to take them... all items can be found on your 
hard-disk ....\airline tycoon2\init\item\location

cheats folder is also on your hard-disk... \airline tycoon2\init\quest\cheats