Extrapolation problem

Hi all, I have a client-server game. I have a moving aircraft in this game. The server updates the aircraft position and direction on a periodic interval basis, and send them to the client. The client has to draw the aircraft every frame, but the update interval from the server is a lot longer than the time needed to draw a frame. Say, the server updates the aircraft 5 times a second, and the client must draw the aircraft 60 times a second. So I need to extrapolate the aircraft position on client. The problem is, I can''t do it right. I don''t know how to solve the ''propagation delay'' problem which occured when the server sends the update to the client. So my aircraft went backward and forward (like blinking). Is there anybody have any idea about this? On each update, the server sends current server time, aircraft current position and current direction. The speed of the aircraft is constant, but the direction may be changed anytime by the server. Thanks a lot for your attention.